diff --git a/examples/activityLog/activityHistory.tsx b/examples/activityLog/activityHistory.tsx
new file mode 100644
index 000000000..05bbce1de
--- /dev/null
+++ b/examples/activityLog/activityHistory.tsx
@@ -0,0 +1,240 @@
+import type { ActivityLogSegmentProps } from '../../lib';
+import { TransmissionList } from '../../lib';
+
+export type ActivitySource = 'activity' | 'notification' | 'label' | 'transmission';
+
+export interface ActivityHistoryEntry {
+  id: string;
+  source: ActivitySource;
+  /** ISO timestamp, also used as the `datetime` of the rendered segment */
+  createdAt: string;
+  /** `activity` only: rendered in bold ahead of the text */
+  actor?: string;
+  /** `activity` | `notification` | `label`: the plain text body */
+  text?: string;
+  /** `transmission` only */
+  sender?: string;
+  senderType?: 'company' | 'person';
+  title?: string;
+  summary?: string;
+}
+
+export const activitySourceLabels: Record<ActivitySource, string> = {
+  activity: 'Hendelser',
+  notification: 'Varslinger',
+  label: 'Merking',
+  transmission: 'Forsendelser',
+};
+
+const monthsNb = [
+  'januar',
+  'februar',
+  'mars',
+  'april',
+  'mai',
+  'juni',
+  'juli',
+  'august',
+  'september',
+  'oktober',
+  'november',
+  'desember',
+];
+
+const osloParts = new Intl.DateTimeFormat('en-GB', {
+  timeZone: 'Europe/Oslo',
+  year: 'numeric',
+  month: 'numeric',
+  day: 'numeric',
+  hour: '2-digit',
+  minute: '2-digit',
+  hour12: false,
+});
+
+/** "22. august 2024 kl. 18.45" */
+export const formatActivityDate = (isoDate: string): string => {
+  const parts = Object.fromEntries(osloParts.formatToParts(new Date(isoDate)).map((part) => [part.type, part.value]));
+  return `${Number(parts.day)}. ${monthsNb[Number(parts.month) - 1]} ${parts.year} kl. ${parts.hour}.${parts.minute}`;
+};
+
+export const activityHistoryEntries: ActivityHistoryEntry[] = [
+  {
+    id: 'l1',
+    source: 'label',
+    createdAt: '2024-08-22T16:45:00Z',
+    text: 'Fantasifull 2024 Søster markerte meldingen som lest.',
+  },
+  {
+    id: 'l2',
+    source: 'label',
+    createdAt: '2024-08-22T11:00:00Z',
+    text: 'Fantasifull 2024 Søster markerte meldingen som ulest.',
+  },
+  {
+    id: 'l3',
+    source: 'label',
+    createdAt: '2024-08-21T13:30:00Z',
+    text: 'Ola Nordmann flyttet meldingen til innboksen.',
+  },
+  {
+    id: 'l4',
+    source: 'label',
+    createdAt: '2024-08-20T12:15:00Z',
+    text: 'Fantasifull 2024 Søster flyttet meldingen til arkivet.',
+  },
+  {
+    id: 'a1',
+    source: 'activity',
+    createdAt: '2024-08-19T09:00:00Z',
+    actor: 'Skatteetaten',
+    text: 'Meldingen ble sendt.',
+  },
+  {
+    id: 'n1',
+    source: 'notification',
+    createdAt: '2024-08-18T11:03:00Z',
+    text: 'Påminnelse på e-post til post@firma-as.no, regnskap@firma-as.no, daglig.leder@firma-as.no og 1 annen mottaker ble levert.',
+  },
+  {
+    id: 't1',
+    source: 'transmission',
+    createdAt: '2024-08-16T09:00:00Z',
+    sender: 'Oslo kommune',
+    senderType: 'company',
+    title: 'Språktest: innhold per språk',
+  },
+  {
+    id: 't2',
+    source: 'transmission',
+    createdAt: '2024-08-15T09:00:00Z',
+    sender: 'Oslo kommune',
+    senderType: 'company',
+    title: 'Sak 7: vises (isAuthorized=true, summary og GUI-vedlegg)',
+  },
+  {
+    id: 't3',
+    source: 'transmission',
+    createdAt: '2024-08-15T08:00:00Z',
+    sender: 'Oslo kommune',
+    senderType: 'company',
+    title: 'Sak 6: deaktivert lenke (isAuthorized=true, uautorisert lenke)',
+  },
+  {
+    id: 't4',
+    source: 'transmission',
+    createdAt: '2024-08-15T06:00:00Z',
+    sender: 'Oslo kommune',
+    senderType: 'company',
+    title: 'Sak 4: vises (isAuthorized=true, innhold finnes)',
+  },
+  {
+    id: 'a2',
+    source: 'activity',
+    createdAt: '2024-08-14T10:30:00Z',
+    actor: 'Skatteetaten',
+    text: 'Meldingen ble åpnet.',
+  },
+  {
+    id: 't5',
+    source: 'transmission',
+    createdAt: '2024-08-13T14:12:00Z',
+    sender: 'Per Nordmann',
+    senderType: 'person',
+    title: 'Tittel 4',
+  },
+  {
+    id: 'n2',
+    source: 'notification',
+    createdAt: '2024-08-13T14:06:00Z',
+    text: 'Varsel på e-post til kari.nordmann@example.com ble levert.',
+  },
+  {
+    id: 'n3',
+    source: 'notification',
+    createdAt: '2024-08-07T11:02:00Z',
+    text: 'Påminnelse på e-post til kari.nordmann@example.com ble levert.',
+  },
+  {
+    id: 'a3',
+    source: 'activity',
+    createdAt: '2024-08-02T08:00:00Z',
+    actor: 'Skatteetaten',
+    text: 'Denne meldingen er utløpt.',
+  },
+  {
+    id: 't6',
+    source: 'transmission',
+    createdAt: '2024-07-31T20:12:00Z',
+    sender: 'Kari Nordmann',
+    senderType: 'person',
+    title: 'Tittel 2',
+  },
+  {
+    id: 'n4',
+    source: 'notification',
+    createdAt: '2024-07-30T20:16:00Z',
+    text: 'Varsel på e-post til kari.nordmann@example.com og post@firma-as.no ble levert.',
+  },
+  {
+    id: 'n5',
+    source: 'notification',
+    createdAt: '2024-07-30T20:15:00Z',
+    text: 'Varsel på SMS til +4799887766 ble levert.',
+  },
+  {
+    id: 't7',
+    source: 'transmission',
+    createdAt: '2024-07-30T20:12:00Z',
+    sender: 'Oslo kommune',
+    senderType: 'company',
+    title: 'Tittel',
+  },
+];
+
+/** Build a log segment from a raw entry, the way a consuming app would. */
+export const toActivityLogSegment = (entry: ActivityHistoryEntry): ActivityLogSegmentProps => {
+  const date = formatActivityDate(entry.createdAt);
+
+  if (entry.source === 'transmission') {
+    return {
+      id: entry.id,
+      kind: entry.source,
+      datetime: entry.createdAt,
+      /** A transmission renders its own card, so nothing readable is left in the
+       *  props — it has to say what its text is. */
+      searchText: [entry.title, entry.summary].filter(Boolean).join(' '),
+      /** ...and take the words back in, to mark them inside that card. */
+      children: (highlightWords) => (
+        <TransmissionList
+          items={[
+            {
+              id: entry.id,
+              title: entry.title,
+              summary: entry.summary,
+              datetime: entry.createdAt,
+              byline: `${entry.sender}, ${date}`,
+              sender: { type: entry.senderType ?? 'company', name: entry.sender ?? '' },
+              highlightWords,
+            },
+          ]}
+        />
+      ),
+    };
+  }
+
+  return {
+    id: entry.id,
+    kind: entry.source,
+    datetime: entry.createdAt,
+    byline: date,
+    summary: entry.actor ? (
+      <>
+        <strong>{entry.actor}</strong>: {entry.text}
+      </>
+    ) : (
+      entry.text
+    ),
+  };
+};
+
+export const activityHistorySegments: ActivityLogSegmentProps[] = activityHistoryEntries.map(toActivityLogSegment);
diff --git a/examples/activityLog/index.ts b/examples/activityLog/index.ts
index f471abfe8..b83f33b1f 100644
--- a/examples/activityLog/index.ts
+++ b/examples/activityLog/index.ts
@@ -1,3 +1,5 @@
 export * from './activityLogItems';
 export * from './useActivityLog';
 export * from './useActivityLogToolbar';
+export * from './activityHistory';
+export * from './useActivityLogFilter';
diff --git a/examples/activityLog/useActivityLogFilter.tsx b/examples/activityLog/useActivityLogFilter.tsx
new file mode 100644
index 000000000..ea3e2a409
--- /dev/null
+++ b/examples/activityLog/useActivityLogFilter.tsx
@@ -0,0 +1,69 @@
+import { useMemo, useState } from 'react';
+import type { ActivityLogSegmentProps, FilterProps, FilterState } from '../../lib';
+import { activityLogKinds } from '../../lib';
+import { type ActivitySource, activitySourceLabels } from './activityHistory';
+
+/** The radio option that stands for "no filter". */
+export const ALL_KINDS = 'all';
+
+const labelFor = (kind: string) => activitySourceLabels[kind as ActivitySource] ?? kind;
+
+/**
+ * A type filter over an activity log: one radio for "all", plus a checkbox per
+ * kind present. Checking every kind is the same as no filter, so it collapses
+ * back onto the radio.
+ */
+export const useActivityLogFilter = (segments: ActivityLogSegmentProps[]) => {
+  const [filterState, setFilterState] = useState<FilterState>({});
+
+  const kinds = useMemo(() => activityLogKinds(segments), [segments]);
+
+  const selected = useMemo(
+    () => (filterState.kind ?? []).map(String).filter((value) => value !== ALL_KINDS),
+    [filterState],
+  );
+
+  const filters: FilterProps[] = useMemo(
+    () => [
+      {
+        id: 'kind',
+        name: 'kind',
+        label: 'Alle typer',
+        title: 'Type ...',
+        groups: { 1: { title: 'Velg type' } },
+        items: [
+          { id: ALL_KINDS, groupId: '1', name: 'kind', role: 'radio', value: ALL_KINDS, title: 'Alle typer' },
+          ...kinds.map((kind) => ({
+            id: kind,
+            groupId: '2',
+            name: 'kind',
+            role: 'checkbox',
+            value: kind,
+            title: labelFor(kind),
+            count: segments.filter((segment) => segment.kind === kind).length,
+          })),
+        ],
+      },
+    ],
+    [kinds, segments],
+  );
+
+  const onFilterStateChange = (next: FilterState) => {
+    const picked = (next.kind ?? []).map(String).filter((value) => value !== ALL_KINDS);
+    const partial = picked.length > 0 && picked.length < kinds.length;
+    setFilterState(partial ? { ...next, kind: picked } : { kind: [ALL_KINDS] });
+  };
+
+  const getFilterLabel = () => {
+    if (selected.length === 0) return 'Alle typer';
+    if (selected.length === 1) return labelFor(selected[0]);
+    return `${selected.length} typer`;
+  };
+
+  return {
+    /** Pass straight to `ActivityLog`. An empty array means every kind. */
+    kind: selected,
+    filter: { filters, filterState, onFilterStateChange, getFilterLabel },
+    reset: () => setFilterState({}),
+  };
+};
diff --git a/examples/activityLog/useActivityLogToolbar.tsx b/examples/activityLog/useActivityLogToolbar.tsx
index 988c8c916..d6943b1b7 100644
--- a/examples/activityLog/useActivityLogToolbar.tsx
+++ b/examples/activityLog/useActivityLogToolbar.tsx
@@ -36,7 +36,7 @@ export const useActivityLogToolbar = (): ToolbarProps => {
 
   const search = {
     name: 'q',
-    placeholder: 'Søk i aktivitetsloggen',
+    placeholder: 'Søk ...',
     value: q,
     onChange,
     onClear,
diff --git a/lib/components/ActivityLog/ActivityLog.stories.tsx b/lib/components/ActivityLog/ActivityLog.stories.tsx
index 9f223a3fa..84c62aefd 100644
--- a/lib/components/ActivityLog/ActivityLog.stories.tsx
+++ b/lib/components/ActivityLog/ActivityLog.stories.tsx
@@ -1,4 +1,4 @@
-import { useState } from 'react';
+import { type ChangeEvent, type ReactNode, useMemo, useState } from 'react';
 import {
   ActivityLog,
   Button,
@@ -10,8 +10,16 @@ import {
   PageBase,
   Section,
   Toolbar,
+  Typography,
 } from '..';
-import { useActivityLog, useProfile } from '../../../examples';
+import {
+  type ActivityHistoryEntry,
+  activityHistoryEntries,
+  toActivityLogSegment,
+  useActivityLog,
+  useActivityLogFilter,
+  useProfile,
+} from '../../../examples';
 
 const meta = {
   title: 'Timeline/ActivityLog',
@@ -98,3 +106,85 @@ export const ActivityLogModalAdvanced = () => {
     </>
   );
 };
+
+const resultsMaxHeight = '60vh';
+
+const ActivityLogEmptyState = ({ children }: { children: ReactNode }) => (
+  <Typography variant="subtle" size="sm">
+    <p>{children}</p>
+  </Typography>
+);
+
+interface DialogActivityLogModalProps {
+  entries: ActivityHistoryEntry[];
+  defaultQuery?: string;
+}
+
+const DialogActivityLogModal = ({ entries, defaultQuery = '' }: DialogActivityLogModalProps) => {
+  const [open, setOpen] = useState<boolean>(true);
+  const [q, setQ] = useState<string>(defaultQuery);
+
+  /** Built once. The query is not baked into them, so typing does not rebuild the log. */
+  const segments = useMemo(() => entries.map(toActivityLogSegment), [entries]);
+
+  const { kind, filter } = useActivityLogFilter(segments);
+
+  const onClose = () => setOpen(false);
+
+  return (
+    <>
+      <Button onClick={() => setOpen(true)}>Open Modal</Button>
+      <ModalBase open={open} onClose={onClose} variant="content">
+        <ModalHeader title="Aktivitetslogg for dialog" onClose={onClose} sticky={false} />
+        <ModalBody>
+          {/* No sticky positioning needed: the log scrolls in its own box below. */}
+          {segments.length > 0 && (
+            <Toolbar
+              filter={filter}
+              search={{
+                name: 'q',
+                label: 'Søk i aktivitetsloggen',
+                placeholder: 'Søk ...',
+                value: q,
+                onChange: (event: ChangeEvent<HTMLInputElement>) => setQ(event.target.value),
+                onClear: () => setQ(''),
+              }}
+            />
+          )}
+          <ActivityLog
+            items={segments}
+            kind={kind}
+            query={q}
+            emptyState={
+              <ActivityLogEmptyState>Det er ikke registrert noen aktiviteter på denne meldingen.</ActivityLogEmptyState>
+            }
+            noResultsState={<ActivityLogEmptyState>Ingen treff</ActivityLogEmptyState>}
+            style={{ maxHeight: resultsMaxHeight, overflowY: 'auto' }}
+          />
+        </ModalBody>
+      </ModalBase>
+    </>
+  );
+};
+
+export const DialogActivityLogFiltered = () => <DialogActivityLogModal entries={activityHistoryEntries} />;
+
+export const DialogActivityLogPartialSources = () => (
+  <DialogActivityLogModal
+    entries={activityHistoryEntries.filter(
+      (entry) => entry.source === 'notification' || entry.source === 'transmission',
+    )}
+  />
+);
+
+export const DialogActivityLogShortLog = () => (
+  <DialogActivityLogModal entries={activityHistoryEntries.filter((entry) => entry.source === 'label').slice(0, 3)} />
+);
+
+/** Empty state 1: the dialog has no activity at all, so there is nothing to filter. */
+export const DialogActivityLogNoActivity = () => <DialogActivityLogModal entries={[]} />;
+
+/** Empty state 2: there is activity, but every term has to match and these two never co-occur. */
+export const DialogActivityLogNoMatches = () => (
+  <DialogActivityLogModal entries={activityHistoryEntries} defaultQuery="sms skatteetaten" />
+);
diff --git a/lib/components/ActivityLog/ActivityLog.tsx b/lib/components/ActivityLog/ActivityLog.tsx
index 2b63f91c0..7cc814556 100644
--- a/lib/components/ActivityLog/ActivityLog.tsx
+++ b/lib/components/ActivityLog/ActivityLog.tsx
@@ -1,42 +1,91 @@
 'use client';
-import { useState } from 'react';
+import { type CSSProperties, type ReactNode, useMemo, useState } from 'react';
 
 import { ActivityLogSegment, type ActivityLogSegmentProps, Button, Section, Timeline } from '..';
+import { activityLogQueryTerms, matchesActivityLogSegment } from './activityLogSearch';
+import { useReservedHeight } from './useReservedHeight';
 
 export interface ActivityLogProps {
   items: ActivityLogSegmentProps[];
   maxItems?: number;
+  /** Allow expanding past `maxItems`. Default is true. */
   collapsible?: boolean;
+  /** Initially expanded. Default is false. */
   expanded?: boolean;
   expandLabel?: string;
   collapseLabel?: string;
+  /** Show only segments with these kinds. Omit, or pass an empty array, for all. */
+  kind?: string | string[];
+  /** Free text; every term has to match. Matches are highlighted. */
+  query?: string;
+  /** Rendered when `items` is empty. */
+  emptyState?: ReactNode;
+  /** Rendered when nothing matches `kind` / `query`. */
+  noResultsState?: ReactNode;
+  /** Keep the unfiltered height while filtering. Default is true. */
+  reserveHeight?: boolean;
+  className?: string;
+  style?: CSSProperties;
 }
 
 export const ActivityLog = ({
   items,
   maxItems,
+  collapsible = true,
+  expanded: defaultExpanded = false,
   expandLabel = 'Expand history',
   collapseLabel = 'Collapse history',
+  kind,
+  query,
+  emptyState,
+  noResultsState,
+  reserveHeight = true,
+  className,
+  style,
 }: ActivityLogProps) => {
-  if (!items?.length) {
-    return null;
-  }
+  const [expanded, setExpanded] = useState<boolean>(defaultExpanded);
+
+  const terms = useMemo(() => activityLogQueryTerms(query), [query]);
+
+  const filterable = kind !== undefined || query !== undefined;
+  const managed =
+    filterable ||
+    emptyState !== undefined ||
+    noResultsState !== undefined ||
+    className !== undefined ||
+    style !== undefined;
 
-  const [expanded, setExpanded] = useState(false);
+  const visible = useMemo(
+    () => (filterable ? (items ?? []).filter((item) => matchesActivityLogSegment(item, kind, terms)) : (items ?? [])),
+    [items, filterable, kind, terms],
+  );
+
+  const filtering = (Array.isArray(kind) ? kind.length > 0 : Boolean(kind)) || terms.length > 0;
+  const { ref, minHeight } = useReservedHeight(filtering, reserveHeight && filterable);
 
   const onToggle = () => {
     setExpanded((prev) => !prev);
   };
 
-  const collapsedItems = maxItems ? items.slice(0, maxItems) : items;
-  const displayedItems = expanded ? items : collapsedItems;
-  const toggle = maxItems && items.length > maxItems;
+  const collapsedItems = maxItems ? visible.slice(0, maxItems) : visible;
+  const displayedItems = expanded ? visible : collapsedItems;
+  const toggle = collapsible && maxItems && visible.length > maxItems;
 
-  return (
+  const log = !items?.length ? (
+    (emptyState ?? null)
+  ) : !visible.length ? (
+    (noResultsState ?? null)
+  ) : (
     <Section spacing={4}>
       <Timeline>
         {displayedItems.map((item) => {
-          return <ActivityLogSegment {...item} key={'activitylog-segment-' + item.id} />;
+          return (
+            <ActivityLogSegment
+              {...item}
+              highlightWords={terms.length ? terms : item.highlightWords}
+              key={'activitylog-segment-' + item.id}
+            />
+          );
         })}
       </Timeline>
       {toggle && (
@@ -46,4 +95,14 @@ export const ActivityLog = ({
       )}
     </Section>
   );
+
+  if (!managed) {
+    return log;
+  }
+
+  return (
+    <div ref={ref} className={className} style={{ ...style, minHeight }}>
+      {log}
+    </div>
+  );
 };
diff --git a/lib/components/ActivityLog/ActivityLogItem.tsx b/lib/components/ActivityLog/ActivityLogItem.tsx
index 6f315aa58..01cd53332 100644
--- a/lib/components/ActivityLog/ActivityLogItem.tsx
+++ b/lib/components/ActivityLog/ActivityLogItem.tsx
@@ -8,8 +8,16 @@ export interface ActivityLogItemProps {
   datetime?: string;
   children?: ReactNode;
   summary?: ReactNode;
+  highlightWords?: string[];
 }
-export const ActivityLogItem = ({ byline, datetime, children, summary, ...props }: ActivityLogItemProps) => {
+export const ActivityLogItem = ({
+  byline,
+  datetime,
+  children,
+  summary,
+  highlightWords,
+  ...props
+}: ActivityLogItemProps) => {
   if (children) {
     return (
       <TimelineActivity byline={byline} datetime={datetime} {...props}>
@@ -20,7 +28,7 @@ export const ActivityLogItem = ({ byline, datetime, children, summary, ...props
 
   return (
     <TimelineActivity byline={byline} datetime={datetime} {...props}>
-      <Typography>{summary}</Typography>
+      <Typography highlightWords={highlightWords}>{summary}</Typography>
     </TimelineActivity>
   );
 };
diff --git a/lib/components/ActivityLog/ActivityLogSegment.tsx b/lib/components/ActivityLog/ActivityLogSegment.tsx
index 729934c90..cf3ba4ac9 100644
--- a/lib/components/ActivityLog/ActivityLogSegment.tsx
+++ b/lib/components/ActivityLog/ActivityLogSegment.tsx
@@ -6,18 +6,33 @@ export interface ActivityLogSegmentProps {
   id?: string;
   items?: ActivityLogItemProps[];
   datetime?: string;
-  byline?: string;
-  children?: ReactNode;
+  byline?: ReactNode;
   summary?: ReactNode;
+  /** May be a function of the words to highlight. */
+  children?: ReactNode | ((highlightWords: string[]) => ReactNode);
+  /** Which source this segment came from. */
+  kind?: string;
+  /** Text to match on. Falls back to the text inside `summary`. */
+  searchText?: string;
+  /** Words to mark in `summary`. Set by `ActivityLog` from its `query`. */
+  highlightWords?: string[];
 }
 
-export const ActivityLogSegment = ({ id, items, datetime, byline, children, summary }: ActivityLogSegmentProps) => {
+export const ActivityLogSegment = ({
+  id,
+  items,
+  datetime,
+  byline,
+  children,
+  summary,
+  highlightWords,
+}: ActivityLogSegmentProps) => {
   return (
     <TimelineSegment datetime={datetime} byline={byline} spacing={2} id={id}>
-      {summary && <Typography>{summary}</Typography>}
-      {children}
+      {summary && <Typography highlightWords={highlightWords}>{summary}</Typography>}
+      {typeof children === 'function' ? children(highlightWords ?? []) : children}
       {items?.map((item) => (
-        <ActivityLogItem {...item} key={'activity-log-item' + item.id} />
+        <ActivityLogItem highlightWords={highlightWords} {...item} key={'activity-log-item' + item.id} />
       ))}
     </TimelineSegment>
   );
diff --git a/lib/components/ActivityLog/__screenshots__/ActivityLog/ActivityLogModalAdvanced.png b/lib/components/ActivityLog/__screenshots__/ActivityLog/ActivityLogModalAdvanced.png
index 850d1d8db..4b059aafe 100644
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diff --git a/lib/components/ActivityLog/__screenshots__/ActivityLog/Controlled.png b/lib/components/ActivityLog/__screenshots__/ActivityLog/Controlled.png
index d0a2587b8..29a430167 100644
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diff --git a/lib/components/ActivityLog/__screenshots__/ActivityLog/DialogActivityLogFiltered.png b/lib/components/ActivityLog/__screenshots__/ActivityLog/DialogActivityLogFiltered.png
new file mode 100644
index 000000000..9d27b8066
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diff --git a/lib/components/ActivityLog/__screenshots__/ActivityLog/DialogActivityLogNoActivity.png b/lib/components/ActivityLog/__screenshots__/ActivityLog/DialogActivityLogNoActivity.png
new file mode 100644
index 000000000..afaa7e347
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diff --git a/lib/components/ActivityLog/__screenshots__/ActivityLog/DialogActivityLogNoMatches.png b/lib/components/ActivityLog/__screenshots__/ActivityLog/DialogActivityLogNoMatches.png
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index 000000000..b49df88f0
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diff --git a/lib/components/ActivityLog/__screenshots__/ActivityLog/DialogActivityLogPartialSources.png b/lib/components/ActivityLog/__screenshots__/ActivityLog/DialogActivityLogPartialSources.png
new file mode 100644
index 000000000..0e21e5eb6
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diff --git a/lib/components/ActivityLog/__screenshots__/ActivityLog/DialogActivityLogShortLog.png b/lib/components/ActivityLog/__screenshots__/ActivityLog/DialogActivityLogShortLog.png
new file mode 100644
index 000000000..36444c090
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diff --git a/lib/components/ActivityLog/__screenshots__/ActivityLog/ProfileActivityLog.png b/lib/components/ActivityLog/__screenshots__/ActivityLog/ProfileActivityLog.png
index 8eb44b0e3..6882d0c80 100644
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diff --git a/lib/components/ActivityLog/activityLogSearch.ts b/lib/components/ActivityLog/activityLogSearch.ts
new file mode 100644
index 000000000..245a18354
--- /dev/null
+++ b/lib/components/ActivityLog/activityLogSearch.ts
@@ -0,0 +1,32 @@
+import { type ReactNode, isValidElement } from 'react';
+import type { ActivityLogSegmentProps } from './ActivityLogSegment';
+
+/** Concatenate the text out of a React node, so a JSX `summary` is searchable. */
+export const activityLogSegmentText = (node: ReactNode): string => {
+  if (typeof node === 'string' || typeof node === 'number') return String(node);
+  if (Array.isArray(node)) return node.map(activityLogSegmentText).join('');
+  if (isValidElement(node)) return activityLogSegmentText((node.props as { children?: ReactNode }).children);
+  return '';
+};
+
+/** Split a query into lower-cased terms. */
+export const activityLogQueryTerms = (query?: string): string[] =>
+  (query ?? '').toLowerCase().split(/\s+/).filter(Boolean);
+
+/** The kinds present in a log, in first-seen order. */
+export const activityLogKinds = (items: ActivityLogSegmentProps[] = []): string[] => [
+  ...new Set(items.map((item) => item.kind).filter((kind): kind is string => Boolean(kind))),
+];
+
+/** Matches when `kind` is one of those asked for and every term appears in the text. */
+export const matchesActivityLogSegment = (
+  segment: ActivityLogSegmentProps,
+  kind: string | string[] | undefined,
+  terms: string[],
+): boolean => {
+  const kinds = kind === undefined ? [] : Array.isArray(kind) ? kind : [kind];
+  if (kinds.length && (segment.kind === undefined || !kinds.includes(segment.kind))) return false;
+  if (!terms.length) return true;
+  const haystack = (segment.searchText ?? activityLogSegmentText(segment.summary)).toLowerCase();
+  return terms.every((term) => haystack.includes(term));
+};
diff --git a/lib/components/ActivityLog/index.ts b/lib/components/ActivityLog/index.ts
index 52bb2eab3..94672d394 100644
--- a/lib/components/ActivityLog/index.ts
+++ b/lib/components/ActivityLog/index.ts
@@ -1,3 +1,5 @@
 export * from './ActivityLog';
 export * from './ActivityLogSegment';
 export * from './ActivityLogItem';
+export * from './activityLogSearch';
+export * from './useReservedHeight';
diff --git a/lib/components/ActivityLog/useReservedHeight.tsx b/lib/components/ActivityLog/useReservedHeight.tsx
new file mode 100644
index 000000000..54978147a
--- /dev/null
+++ b/lib/components/ActivityLog/useReservedHeight.tsx
@@ -0,0 +1,25 @@
+'use client';
+import { useLayoutEffect, useRef, useState } from 'react';
+
+/** Hold the height an element had while `hold` was false, so filtering cannot shrink it. */
+export const useReservedHeight = (hold: boolean, enabled = true) => {
+  const ref = useRef<HTMLDivElement>(null);
+  const [reserved, setReserved] = useState<number>();
+
+  useLayoutEffect(() => {
+    const element = ref.current;
+    if (!element || !enabled || hold) return;
+
+    const update = () => {
+      const { height } = element.getBoundingClientRect();
+      setReserved((prev) => (prev !== undefined && Math.abs(prev - height) < 1 ? prev : height));
+    };
+
+    update();
+    const observer = new ResizeObserver(update);
+    observer.observe(element);
+    return () => observer.disconnect();
+  }, [enabled, hold]);
+
+  return { ref, minHeight: enabled ? reserved : undefined };
+};
diff --git a/lib/components/Dialog/DialogActivityLog.stories.ts b/lib/components/Dialog/DialogActivityLog.stories.ts
deleted file mode 100644
index 343675d40..000000000
--- a/lib/components/Dialog/DialogActivityLog.stories.ts
+++ /dev/null
@@ -1,25 +0,0 @@
-import type { Meta, StoryObj } from '@storybook/react-vite';
-import { dialog, dialogActivityLog } from '../../../examples';
-import { DialogActivityLog } from './DialogActivityLog.tsx';
-
-const meta = {
-  title: 'Inbox/Dialog/DialogActivityLog',
-  component: DialogActivityLog,
-  tags: [],
-  args: {
-    ...dialogActivityLog,
-    title: dialog.title,
-  },
-} satisfies Meta<typeof DialogActivityLog>;
-
-export default meta;
-type Story = StoryObj<typeof meta>;
-
-export const Default: Story = {
-  args: {
-    open: true,
-    onClose: () => {
-      alert('Close activityLog');
-    },
-  },
-};
diff --git a/lib/components/Dialog/DialogActivityLog.stories.tsx b/lib/components/Dialog/DialogActivityLog.stories.tsx
new file mode 100644
index 000000000..47dfd3a32
--- /dev/null
+++ b/lib/components/Dialog/DialogActivityLog.stories.tsx
@@ -0,0 +1,71 @@
+import { type ChangeEvent, type ReactNode, useState } from 'react';
+import { Button, Typography } from '..';
+import { activityHistorySegments, dialog, dialogActivityLog, useActivityLogFilter } from '../../../examples';
+import { DialogActivityLog } from './DialogActivityLog.tsx';
+
+const meta = {
+  title: 'Inbox/Dialog/DialogActivityLog',
+  component: DialogActivityLog,
+  tags: [],
+  args: {
+    ...dialogActivityLog,
+    title: dialog.title,
+  },
+};
+
+export default meta;
+
+export const Default = {
+  args: {
+    open: true,
+    onClose: () => {
+      alert('Close activityLog');
+    },
+  },
+};
+
+const EmptyState = ({ children }: { children: ReactNode }) => (
+  <Typography variant="subtle" size="sm">
+    <p>{children}</p>
+  </Typography>
+);
+
+/**
+ * The wrapper forwards every `ActivityLog` prop and renders `toolbar` above the
+ * log. The type filter is multi-select: check any number of types, and checking
+ * every one of them collapses back onto "Alle typer".
+ */
+export const WithFilterAndSearch = () => {
+  const [open, setOpen] = useState<boolean>(true);
+  const [q, setQ] = useState<string>('');
+
+  const { kind, filter } = useActivityLogFilter(activityHistorySegments);
+
+  return (
+    <>
+      <Button onClick={() => setOpen(true)}>Open Modal</Button>
+      <DialogActivityLog
+        title="Aktivitetslogg for dialog"
+        open={open}
+        onClose={() => setOpen(false)}
+        items={activityHistorySegments}
+        kind={kind}
+        query={q}
+        toolbar={{
+          filter,
+          search: {
+            name: 'q',
+            label: 'Søk i aktivitetsloggen',
+            placeholder: 'Søk ...',
+            value: q,
+            onChange: (event: ChangeEvent<HTMLInputElement>) => setQ(event.target.value),
+            onClear: () => setQ(''),
+          },
+        }}
+        emptyState={<EmptyState>Det er ikke registrert noen aktiviteter på denne meldingen.</EmptyState>}
+        noResultsState={<EmptyState>Ingen treff</EmptyState>}
+        style={{ maxHeight: '60vh', overflowY: 'auto' }}
+      />
+    </>
+  );
+};
diff --git a/lib/components/Dialog/DialogActivityLog.tsx b/lib/components/Dialog/DialogActivityLog.tsx
index a8cb56d19..f626a2ef7 100644
--- a/lib/components/Dialog/DialogActivityLog.tsx
+++ b/lib/components/Dialog/DialogActivityLog.tsx
@@ -1,18 +1,20 @@
-import { ActivityLog, type ActivityLogProps, ModalBase, ModalBody, ModalHeader, type ToolbarProps } from '../';
+import { ActivityLog, type ActivityLogProps, ModalBase, ModalBody, ModalHeader, Toolbar, type ToolbarProps } from '../';
 
 export interface DialogActivityLogProps extends ActivityLogProps {
   title: string;
+  /** Rendered above the log, for a filter and a search over it. */
   toolbar?: ToolbarProps;
   open: boolean;
   onClose: () => void;
 }
 
-export const DialogActivityLog = ({ title, items, open, onClose }: DialogActivityLogProps) => {
+export const DialogActivityLog = ({ title, toolbar, open, onClose, ...activityLog }: DialogActivityLogProps) => {
   return (
     <ModalBase open={open} onClose={onClose} variant="content">
       <ModalHeader title={title} onClose={onClose} />
       <ModalBody>
-        <ActivityLog items={items} />
+        {toolbar && <Toolbar {...toolbar} />}
+        <ActivityLog {...activityLog} />
       </ModalBody>
     </ModalBase>
   );
diff --git a/lib/components/Dialog/__screenshots__/DialogActivityLog/WithFilterAndSearch.png b/lib/components/Dialog/__screenshots__/DialogActivityLog/WithFilterAndSearch.png
new file mode 100644
index 000000000..959fda63a
Binary files /dev/null and b/lib/components/Dialog/__screenshots__/DialogActivityLog/WithFilterAndSearch.png differ
diff --git a/lib/components/Dropdown/Dropdown.tsx b/lib/components/Dropdown/Dropdown.tsx
index 71cabc0ce..db5277bed 100644
--- a/lib/components/Dropdown/Dropdown.tsx
+++ b/lib/components/Dropdown/Dropdown.tsx
@@ -92,12 +92,23 @@ export const Dropdown = ({
   expanded = false,
 }: DropdownProps) => {
   const containerRef = useRef<HTMLDivElement>(null);
+  const [portalTarget, setPortalTarget] = useState<HTMLElement | null>(null);
   const dropdownRef = useRef<HTMLDivElement>(null);
   const openRef = useRef(open);
   useEffect(() => {
     openRef.current = open;
   }, [open]);
 
+  /** A <dialog> paints in the top layer, so portalling to document.body would put
+   *  the dropdown behind the modal. Stay inside the dialog when there is one. */
+  useEffect(() => {
+    if (!useFixedPosition) {
+      setPortalTarget(null);
+      return;
+    }
+    setPortalTarget(containerRef.current?.closest('dialog') ?? document.body);
+  }, [useFixedPosition]);
+
   const [coords, setCoords] = useState<{
     yDir: string;
     xDir: string;
@@ -322,7 +333,7 @@ export const Dropdown = ({
       {backdrop && <div className={styles.backdrop} aria-hidden={!open} />}
       <div id={id + '-root'} ref={containerRef} style={{ position: 'relative', display: 'inline-block' }}>
         {trigger}
-        {useFixedPosition ? createPortal(dropdownEl, document.body) : dropdownEl}
+        {useFixedPosition && portalTarget ? createPortal(dropdownEl, portalTarget) : dropdownEl}
       </div>
     </>
   );
diff --git a/lib/components/Toolbar/ToolbarFilterMenu.tsx b/lib/components/Toolbar/ToolbarFilterMenu.tsx
index d5159fb61..3f14a81bf 100644
--- a/lib/components/Toolbar/ToolbarFilterMenu.tsx
+++ b/lib/components/Toolbar/ToolbarFilterMenu.tsx
@@ -115,6 +115,7 @@ export const ToolbarFilterMenu = ({
   if (removable) {
     return (
       <Dropdown
+        useFixedPosition
         submitLabel={submitLabel}
         title={title}
         variant="drawer-dropdown"
@@ -160,6 +161,7 @@ export const ToolbarFilterMenu = ({
 
   return (
     <Dropdown
+      useFixedPosition
       size={dropdownSize}
       title={title}
       variant="drawer-dropdown"
diff --git a/lib/components/Toolbar/useFilter.tsx b/lib/components/Toolbar/useFilter.tsx
index 28f203bd9..3c599b335 100644
--- a/lib/components/Toolbar/useFilter.tsx
+++ b/lib/components/Toolbar/useFilter.tsx
@@ -73,6 +73,15 @@ export const useFilter = ({ filters = [], filterState, onFilterStateChange }: Us
     });
   }, [filters, applicableFilterState]);
 
+  /** Values of radio options sharing a name, which checkboxes under that name replace. */
+  const radioValuesFor = (name: string) =>
+    new Set(
+      filters
+        .flatMap((filter) => filter.items ?? [])
+        .filter((option) => option.name === name && option.role === 'radio' && option.value !== undefined)
+        .map((option) => String(option.value)),
+    );
+
   const onFilterChange = (type: string, name: string, value: string) => {
     const values = [value];
 
@@ -81,16 +90,19 @@ export const useFilter = ({ filters = [], filterState, onFilterStateChange }: Us
         ...applicableFilterState,
         [name]: values,
       });
-    } else {
-      changeFilterState({
-        ...applicableFilterState,
-        [name]: applicableFilterState[name]
-          ? applicableFilterState[name].some((v) => values.includes(String(v)))
-            ? applicableFilterState[name].filter((v) => !(values || []).includes(String(v)))
-            : [...applicableFilterState[name], ...(values || [])]
-          : values,
-      });
+      return;
     }
+
+    /** A radio and a checkbox under one name are alternatives, never both at once. */
+    const radioValues = radioValuesFor(name);
+    const current = (applicableFilterState[name] ?? []).filter((v) => !radioValues.has(String(v)));
+
+    changeFilterState({
+      ...applicableFilterState,
+      [name]: current.some((v) => values.includes(String(v)))
+        ? current.filter((v) => !values.includes(String(v)))
+        : [...current, ...values],
+    });
   };
 
   const onFilterRemove = (name: string) => {