Workspace selection dialog not rendered correctly in dark theme

[Phillipus]

Using eclipse-SDK-I20260416-1800-macosx-cocoa-aarch64 on Mac:

[iloveeclipse]

Regression from #3895.
@vogella : could you please check?

[vogella]

Linux:

I check in the code.

[vogella]

@Phillipus can you run this Snippet with the latest SWT (from yesterday) and post the screenshots here:

//
// Reproduces the widget mix from ChooseWorkspaceDialog + ChooseWorkspaceWithSettingsDialog
// so we can see which controls Cocoa's dark NSAppearance handles correctly, and which are
// broken by the recursive setBackground/setForeground walk introduced in PR 3895.
//
// Run on Mac (aarch64 example):
//   SWT=~/.m2/repository/org/eclipse/platform/org.eclipse.swt.cocoa.macosx.aarch64/<version>/org.eclipse.swt.cocoa.macosx.aarch64-<version>.jar
//   javac -cp "$SWT" /tmp/DarkThemeSnippet.java -d /tmp
//   java  -XstartOnFirstThread -cp "$SWT:/tmp" DarkThemeSnippet
//
// On Linux GTK, swap the jar for org.eclipse.swt.gtk.linux.x86_64 and drop -XstartOnFirstThread.

import org.eclipse.swt.*;
import org.eclipse.swt.custom.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.widgets.*;

public final class DarkThemeSnippet {

	// Exact colors from IDEApplication.applyDarkStyles
	private static final int[] BG_RGB   = { 72, 72, 76 };   // #48484c
	private static final int[] FG_RGB   = { 238, 238, 238 }; // #eeeeee
	private static final int[] LINK_RGB = { 111, 197, 238 }; // #6fc5ee

	public static void main(String[] args) {
		Display display = new Display();
		// Same call IDEApplication.initializeDefaultTheme makes when isDark == true.
		display.setDarkThemePreferred(true);

		Color bg   = new Color(display, BG_RGB[0],   BG_RGB[1],   BG_RGB[2]);
		Color fg   = new Color(display, FG_RGB[0],   FG_RGB[1],   FG_RGB[2]);
		Color link = new Color(display, LINK_RGB[0], LINK_RGB[1], LINK_RGB[2]);

		Shell a = buildShell(display, "A: Cocoa dark only (no applyStylesRecursive)", false, bg, fg, link);
		Shell b = buildShell(display, "B: Cocoa dark + PR 3895 recursive styling",    true,  bg, fg, link);

		Point aSize = a.computeSize(SWT.DEFAULT, SWT.DEFAULT);
		Point bSize = b.computeSize(SWT.DEFAULT, SWT.DEFAULT);
		a.setSize(Math.max(aSize.x, 560), Math.max(aSize.y, 480));
		b.setSize(Math.max(bSize.x, 560), Math.max(bSize.y, 480));
		a.setLocation(60, 80);
		b.setLocation(60 + a.getSize().x + 30, 80);

		a.open();
		b.open();

		while (!a.isDisposed() || !b.isDisposed()) {
			if (!display.readAndDispatch()) {
				display.sleep();
			}
		}
		display.dispose();
	}

	private static Shell buildShell(Display display, String title, boolean applyStyles,
			Color bg, Color fg, Color linkColor) {
		Shell shell = new Shell(display, SWT.SHELL_TRIM);
		shell.setText(title);
		GridLayout shellLayout = new GridLayout(1, false);
		shellLayout.marginWidth = 16;
		shellLayout.marginHeight = 16;
		shell.setLayout(shellLayout);

		// Title line (mimics TitleAreaDialog title)
		Label header = new Label(shell, SWT.NONE);
		header.setText("Select a directory as workspace");

		Label desc = new Label(shell, SWT.WRAP);
		desc.setText("Eclipse SDK uses the workspace directory to store its preferences and development artifacts.");
		GridData descGd = new GridData(SWT.FILL, SWT.CENTER, true, false);
		descGd.widthHint = 480;
		desc.setLayoutData(descGd);

		// Workspace combo + Browse button (createWorkspaceBrowseRow)
		Composite row = new Composite(shell, SWT.NONE);
		row.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true, false));
		GridLayout rowLayout = new GridLayout(2, false);
		rowLayout.marginWidth = 0;
		row.setLayout(rowLayout);

		Combo combo = new Combo(row, SWT.DROP_DOWN);
		combo.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true, false));
		combo.add("/Users/me/eclipse-workspace");
		combo.add("/Users/me/projects/demo");
		combo.select(0);

		Button browse = new Button(row, SWT.PUSH);
		browse.setText("Browse...");

		// Also add a plain Text so we can see how SWT.BORDER text fields render.
		Text text = new Text(shell, SWT.BORDER);
		text.setText("Plain Text widget (not in real dialog, included for comparison)");
		text.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true, false));

		// Recent Workspaces section (createRecentWorkspacesComposite)
		Label recent = new Label(shell, SWT.NONE);
		recent.setText("Recent Workspaces");

		Link link1 = new Link(shell, SWT.NONE);
		link1.setText("<a>/Users/me/eclipse-workspace</a>");
		Link link2 = new Link(shell, SWT.NONE);
		link2.setText("<a>/Users/me/projects/demo</a>");

		// Copy Settings section (ChooseWorkspaceWithSettingsDialog.createSettingsControls)
		ScrolledComposite sc = new ScrolledComposite(shell, SWT.V_SCROLL | SWT.H_SCROLL);
		sc.setExpandHorizontal(true);
		sc.setExpandVertical(true);
		GridData scGd = new GridData(SWT.FILL, SWT.FILL, true, true);
		scGd.heightHint = 140;
		sc.setLayoutData(scGd);

		Composite body = new Composite(sc, SWT.NONE);
		body.setLayout(new GridLayout(1, false));
		sc.setContent(body);

		Composite hdr = new Composite(body, SWT.NONE);
		GridLayout hdrLayout = new GridLayout(2, false);
		hdrLayout.marginWidth = 0;
		hdrLayout.marginHeight = 0;
		hdr.setLayout(hdrLayout);
		Label toggle = new Label(hdr, SWT.NONE);
		toggle.setText("\u25BE"); // ▾
		Label settingsLabel = new Label(hdr, SWT.NONE);
		settingsLabel.setText("Copy Settings");

		Composite section = new Composite(body, SWT.NONE);
		RowLayout rl = new RowLayout(SWT.VERTICAL);
		rl.marginLeft = 14;
		rl.spacing = 6;
		section.setLayout(rl);

		// These SWT.CHECK buttons are what shows up as white rectangles on Mac in issue #3897.
		Button c1 = new Button(section, SWT.CHECK);
		c1.setText("Workbench Layout");
		Button c2 = new Button(section, SWT.CHECK);
		c2.setText("Working Sets");
		Button c3 = new Button(section, SWT.CHECK);
		c3.setText("Key Bindings");

		body.setSize(body.computeSize(SWT.DEFAULT, SWT.DEFAULT));
		sc.setMinSize(body.computeSize(SWT.DEFAULT, SWT.DEFAULT));

		// Button bar (Launch/Cancel), mirrors createButtonsForButtonBar
		Composite btns = new Composite(shell, SWT.NONE);
		btns.setLayoutData(new GridData(SWT.END, SWT.CENTER, true, false));
		btns.setLayout(new GridLayout(2, true));
		Button cancel = new Button(btns, SWT.PUSH);
		cancel.setText("Cancel");
		Button launch = new Button(btns, SWT.PUSH);
		launch.setText("Launch");

		if (applyStyles) {
			applyDarkStyles(shell, bg, fg, linkColor);
		}

		return shell;
	}

	/** Faithful copy of IDEApplication.applyDarkStyles / applyStylesRecursive (without ExpandableComposite). */
	private static void applyDarkStyles(Shell shell, Color bg, Color fg, Color linkColor) {
		shell.setBackground(bg);
		shell.setForeground(fg);
		applyStylesRecursive(shell, bg, fg, linkColor);
	}

	private static void applyStylesRecursive(Control control, Color bg, Color fg, Color linkColor) {
		control.setBackground(bg);
		if (control instanceof Link link) {
			link.setLinkForeground(linkColor);
		} else {
			control.setForeground(fg);
		}
		if (control instanceof Composite composite) {
			for (Control child : composite.getChildren()) {
				applyStylesRecursive(child, bg, fg, linkColor);
			}
		}
	}
}

If you set the default theme to dark, how does the workspace selection dialog look like? See https://eclipse.dev/eclipse/markdown/?f=news/4.40/platform.md for the default theme setting.

[Phillipus]

[Phillipus]

If you set the default theme to dark, how does the workspace selection dialog look like? See https://eclipse.dev/eclipse/markdown/?f=news/4.40/platform.md for the default theme setting.

The same as in the OP.

[vogella]

If you set the default theme to dark, how does the workspace selection dialog look like? See https://eclipse.dev/eclipse/markdown/?f=news/4.40/platform.md for the default theme setting.

The same as in the OP.

The initial ws selection dialog does not have the "Copy Settings" section, so are you saying it look correctly styled dark?

[vogella]

Ok, here is my theory:

applyDarkStyles(shell) styles the widget tree during createContents, Composite.getChildren() returns invisible children too, so they are visited.

On Cocoa, native NSButton instances that were never realized/painted don't reliably retain color overrides set while hidden. When the user clicks the toggle and the section becomes visible, Cocoa draws them with white system defaults

On GTK, hidden-widget color state is retained across realize, so Linux looks fine.

Can you test this snippet?

// Self-contained SWT snippet v2 for https://github.com/eclipse-platform/eclipse.platform.ui/issues/3897
//
// Reproduces the real-dialog scenario: the "Copy Settings" section starts HIDDEN
// (expanded=false) because ChooseWorkspaceWithSettingsDialog.createSettingsControls
// calls sectionClient.setVisible(false) on first launch. Dark styling runs during
// createContents, then the user clicks the toggle to expand the section.
//
// Shell 1 = current behavior — styling runs once at startup only.
// Shell 2 = proposed minimal fix — SWT.Show listener on the section re-applies styles
//           when the section becomes visible.
//
// Expected on Mac (Cocoa):
//   Shell 1 — after clicking the toggle arrow, checkboxes render as bright/white bars.
//   Shell 2 — after clicking the toggle arrow, checkboxes render with dark bg + fg.
//
// Run on Mac aarch64:
//   SWT=~/.m2/repository/org/eclipse/platform/org.eclipse.swt.cocoa.macosx.aarch64/<ver>/org.eclipse.swt.cocoa.macosx.aarch64-<ver>.jar
//   javac -cp "$SWT" /tmp/DarkThemeSnippet2.java -d /tmp
//   java  -XstartOnFirstThread -cp "$SWT:/tmp" DarkThemeSnippet2

import org.eclipse.swt.*;
import org.eclipse.swt.custom.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.widgets.*;

public final class DarkThemeSnippet2 {

	// Exact colors from IDEApplication.applyDarkStyles
	private static final int[] BG_RGB   = { 72, 72, 76 };   // #48484c
	private static final int[] FG_RGB   = { 238, 238, 238 }; // #eeeeee
	private static final int[] LINK_RGB = { 111, 197, 238 }; // #6fc5ee

	public static void main(String[] args) {
		Display display = new Display();
		display.setDarkThemePreferred(true);

		Color bg   = new Color(display, BG_RGB[0],   BG_RGB[1],   BG_RGB[2]);
		Color fg   = new Color(display, FG_RGB[0],   FG_RGB[1],   FG_RGB[2]);
		Color link = new Color(display, LINK_RGB[0], LINK_RGB[1], LINK_RGB[2]);

		Shell buggy = buildShell(display, "1: Current behavior (no fix) — expand to reproduce", false, bg, fg, link);
		Shell fixed = buildShell(display, "2: Minimal fix — SWT.Show listener on section",      true,  bg, fg, link);

		Point s1 = buggy.computeSize(SWT.DEFAULT, SWT.DEFAULT);
		Point s2 = fixed.computeSize(SWT.DEFAULT, SWT.DEFAULT);
		buggy.setSize(Math.max(s1.x, 560), Math.max(s1.y, 480));
		fixed.setSize(Math.max(s2.x, 560), Math.max(s2.y, 480));
		buggy.setLocation(60, 80);
		fixed.setLocation(60 + buggy.getSize().x + 30, 80);

		buggy.open();
		fixed.open();

		while (!buggy.isDisposed() || !fixed.isDisposed()) {
			if (!display.readAndDispatch()) {
				display.sleep();
			}
		}
		display.dispose();
	}

	private static Shell buildShell(Display display, String title, boolean installFix,
			Color bg, Color fg, Color linkColor) {
		Shell shell = new Shell(display, SWT.SHELL_TRIM);
		shell.setText(title);
		GridLayout shellLayout = new GridLayout(1, false);
		shellLayout.marginWidth = 16;
		shellLayout.marginHeight = 16;
		shell.setLayout(shellLayout);

		Label header = new Label(shell, SWT.NONE);
		header.setText("Select a directory as workspace");

		Label desc = new Label(shell, SWT.WRAP);
		desc.setText("Eclipse SDK uses the workspace directory to store its preferences and development artifacts.");
		GridData descGd = new GridData(SWT.FILL, SWT.CENTER, true, false);
		descGd.widthHint = 480;
		desc.setLayoutData(descGd);

		// Workspace combo + Browse button
		Composite row = new Composite(shell, SWT.NONE);
		row.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true, false));
		GridLayout rowLayout = new GridLayout(2, false);
		rowLayout.marginWidth = 0;
		row.setLayout(rowLayout);
		Combo combo = new Combo(row, SWT.DROP_DOWN);
		combo.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true, false));
		combo.add("/Users/me/eclipse-workspace");
		combo.select(0);
		Button browse = new Button(row, SWT.PUSH);
		browse.setText("Browse...");

		// Recent Workspaces
		Label recent = new Label(shell, SWT.NONE);
		recent.setText("Recent Workspaces");
		Link link1 = new Link(shell, SWT.NONE);
		link1.setText("<a>/Users/me/eclipse-workspace</a>");

		// --- Copy Settings section (matches ChooseWorkspaceWithSettingsDialog) ---
		ScrolledComposite sc = new ScrolledComposite(shell, SWT.V_SCROLL | SWT.H_SCROLL);
		sc.setExpandHorizontal(true);
		sc.setExpandVertical(true);
		GridData scGd = new GridData(SWT.FILL, SWT.FILL, true, true);
		scGd.heightHint = 160;
		sc.setLayoutData(scGd);

		Composite body = new Composite(sc, SWT.NONE);
		body.setLayout(new GridLayout(1, false));
		sc.setContent(body);

		Composite hdr = new Composite(body, SWT.NONE);
		GridLayout hdrLayout = new GridLayout(2, false);
		hdrLayout.marginWidth = 0;
		hdrLayout.marginHeight = 0;
		hdr.setLayout(hdrLayout);
		Label toggle = new Label(hdr, SWT.NONE);
		Label settingsLabel = new Label(hdr, SWT.NONE);
		settingsLabel.setText("Copy Settings  (click the arrow to expand)");

		Composite sectionClient = new Composite(body, SWT.NONE);
		GridData clientData = new GridData(SWT.FILL, SWT.FILL, true, false);
		sectionClient.setLayoutData(clientData);
		RowLayout rl = new RowLayout(SWT.VERTICAL);
		rl.marginLeft = 14;
		rl.spacing = 6;
		sectionClient.setLayout(rl);

		// Exactly as in the real dialog: buttons always created, section hidden on first launch
		new Button(sectionClient, SWT.CHECK).setText("Workbench Layout");
		new Button(sectionClient, SWT.CHECK).setText("Working Sets");
		new Button(sectionClient, SWT.CHECK).setText("Key Bindings");

		boolean expanded = false; // first-launch state: no prior settings
		sectionClient.setVisible(expanded);
		clientData.exclude = !expanded;
		toggle.setText(expanded ? "\u25BE" : "\u25B8");

		Listener toggleListener = e -> {
			boolean newState = !sectionClient.getVisible();
			sectionClient.setVisible(newState);
			((GridData) sectionClient.getLayoutData()).exclude = !newState;
			toggle.setText(newState ? "\u25BE" : "\u25B8");
			body.layout(true);
			sc.setMinSize(body.computeSize(SWT.DEFAULT, SWT.DEFAULT));
			shell.layout(true, true);
		};
		toggle.addListener(SWT.MouseDown, toggleListener);
		settingsLabel.addListener(SWT.MouseDown, toggleListener);

		body.setSize(body.computeSize(SWT.DEFAULT, SWT.DEFAULT));
		sc.setMinSize(body.computeSize(SWT.DEFAULT, SWT.DEFAULT));

		Composite btns = new Composite(shell, SWT.NONE);
		btns.setLayoutData(new GridData(SWT.END, SWT.CENTER, true, false));
		btns.setLayout(new GridLayout(2, true));
		new Button(btns, SWT.PUSH).setText("Cancel");
		new Button(btns, SWT.PUSH).setText("Launch");

		// Apply dark styling once — mirrors IDEApplication.createContents override.
		applyDarkStyles(shell, bg, fg, linkColor);

		// ---- Minimal fix: when the hidden section becomes visible, re-apply styling.
		// We listen for SWT.Show on sectionClient itself. SWT fires Show on a Control
		// when setVisible(true) is called while the parent shell is already visible.
		if (installFix) {
			sectionClient.addListener(SWT.Show, e -> applyStylesRecursive(sectionClient, bg, fg, linkColor));
		}

		return shell;
	}

	private static void applyDarkStyles(Shell shell, Color bg, Color fg, Color linkColor) {
		shell.setBackground(bg);
		shell.setForeground(fg);
		applyStylesRecursive(shell, bg, fg, linkColor);
	}

	private static void applyStylesRecursive(Control control, Color bg, Color fg, Color linkColor) {
		control.setBackground(bg);
		if (control instanceof Link link) {
			link.setLinkForeground(linkColor);
		} else {
			control.setForeground(fg);
		}
		if (control instanceof Composite composite) {
			for (Control child : composite.getChildren()) {
				applyStylesRecursive(child, bg, fg, linkColor);
			}
		}
	}
}

[vogella]

@Phillipus if the snippet confirms the theory, the linked PR should fix it.

[Phillipus]

With the latest snippet:

[Phillipus]

The initial ws selection dialog does not have the "Copy Settings" section, so are you saying it look correctly styled dark?

That one is OK:

[vogella]

With the latest snippet:

You are awesome @Phillipus thanks for testing. #3899 should solve the Mac styling issue. Do you want to test or shall I just blindly merge and we see in tomorrows I-Build?