Admin sidebar causes page-level scrolling and scrolls with channel content

[oshuej198]

Description

On admin pages, the local admin navigation participates in the document's main scroll flow. Its content expands the whole page vertically, which creates an unnecessary page-level scrollbar. When the page is scrolled, the admin navigation moves together with the channels table and the rest of the content.

This makes the page difficult to use because both the page controls and the top of the admin navigation disappear from the viewport.

Steps to reproduce

1. Open /admin/channels on a desktop viewport.
2. Expand the main application sidebar.
3. Observe the vertical scrollbar on the whole document.
4. Scroll the page down.

Actual behavior

• The document becomes much taller than the viewport because of the admin navigation.
• The admin navigation and the channel content share the same scroll container.
• Scrolling the page moves both the local navigation and the table out of the viewport.
• The issue occurs with both the expanded and collapsed main application sidebar.

Expected behavior

• The application shell should fit within the viewport without an unnecessary document-level scrollbar.
• The admin navigation should remain within the viewport.
• If the navigation items do not fit, the admin navigation should have its own internal vertical scrolling.
• The page content/table should scroll independently from the local navigation.
• Expanding the main application sidebar should affect only the available horizontal space.

Reproduction environment

• Local development build
• Route: /admin/channels
• Desktop viewport: 1512 × 844

Technical observations

• window.innerHeight: 844 px
• document.documentElement.scrollHeight: 1850 px
• Admin sidebar height: approximately 1783 px
• Admin sidebar styles include position: static and overflow-y: visible
• At window.scrollY = 720, both the sidebar and table are shifted outside the viewport.

Acceptance criteria

• No document-level vertical scrollbar is introduced by the admin navigation.
• The admin navigation scrolls independently when its content exceeds the viewport.
• Scrolling the channels content does not move the local admin navigation.
• The behavior works with both expanded and collapsed main application sidebar.
• The fix is verified at common desktop viewport sizes.

Screenshots

Before scrolling — page-level scrollbar is visible:

After scrolling — the table is outside the viewport and the local admin navigation has moved with it:

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P.S. Although the issue is demonstrated on /admin/channels, it is not specific to the admin area. This appears to be a global application layout and scrolling problem. The admin page is used here only as a clear reproducible example; the fix should be implemented at the shared application shell/layout level and verified across other sections of the application.

[oshuej198]

Hi @stefan-ernst!

I’d like to work on this issue and implement the fix.
I plan to address the scrolling behavior at the shared application layout level, ensure that local sidebars remain within the viewport and scroll independently, and verify the result across admin and other application sections with the main sidebar both expanded and collapsed.

If this approach matches the expected UX, could you please assign the issue to me?
I’ll submit a PR once the implementation is ready.

[stefan-ernst]

Hey @oshuej198 - PR welcome! The only concern I have is that if the admin sidebar scrolls independently, the UX could end up a bit more fiddly. You have to judge it yourself if its more usable this way, happy to test the result