Style workspace selection dialog with default theme setting

Read the default theme from UserScope, scoped by product or application
ID
(falling back to the base node for backwards compatibility), to
determine
whether dark mode should be applied before the workbench starts.

Apply dark styling to the workspace selection dialog
(ChooseWorkspaceDialog
and ChooseWorkspaceWithSettingsDialog) by setting shell
background/foreground
colors and propagating them recursively to child controls. Link
foreground is set to the same value as the default dark theme.

The ExpandableComposite title bar foreground is explicitly set to match
the
parent composite foreground so it remains readable in both light and
dark themes.

After the workspace selection dialog reset early dark theme styling
before the workbench starts the ThemeEngine will apply the correct theme
from here on.

Author: vogella

bundles/org.eclipse.e4.ui.css.swt.theme/META-INF/MANIFEST.MF

@@ -6,7 +6,7 @@ Bundle-Name: %pluginName
 Bundle-Vendor: %providerName
 Bundle-Localization: plugin
 Bundle-RequiredExecutionEnvironment: JavaSE-21
-Require-Bundle: org.eclipse.swt;bundle-version="[3.133.0,4.0.0)",
+Require-Bundle: org.eclipse.swt;bundle-version="[3.134.0,4.0.0)",
  org.eclipse.e4.ui.css.swt;bundle-version="0.13.100",
  org.eclipse.e4.ui.css.core;bundle-version="0.12.200",
  org.eclipse.core.runtime;bundle-version="[3.29.0,4.0.0)"

bundles/org.eclipse.e4.ui.css.swt.theme/src/org/eclipse/e4/ui/css/swt/internal/theme/ThemeEngine.java

@@ -510,6 +510,9 @@ public void setTheme(ITheme theme, boolean restore, boolean force) {
 				ThemeEngineManager.logError(e.getMessage(), e);
 			}
 		}
+		boolean isDark = theme.getId().contains("dark"); //$NON-NLS-1$
+		display.setDarkThemePreferred(isDark);
+
 		sendThemeChangeEvent(restore);
 
 		for (CSSEngine engine : cssEngines) {

bundles/org.eclipse.ui.ide.application/META-INF/MANIFEST.MF

@@ -18,6 +18,7 @@ Require-Bundle: org.eclipse.ui.ide;bundle-version="[3.21.0,4.0.0)",
  org.eclipse.e4.core.di.extensions,
  org.eclipse.e4.core.services;bundle-version="2.4.0",
  org.eclipse.e4.core.contexts;bundle-version="[1.12.0,2.0.0)",
+ org.eclipse.ui.forms,
  org.eclipse.urischeme;bundle-version="[1.3.0,2.0.0)",
  org.eclipse.e4.ui.di
 Export-Package: org.eclipse.ui.internal.ide.application;x-internal:=true,

bundles/org.eclipse.ui.ide.application/src/org/eclipse/ui/internal/ide/application/IDEApplication.java

@@ -36,12 +36,15 @@
 
 import org.eclipse.core.runtime.IConfigurationElement;
 import org.eclipse.core.runtime.IExecutableExtension;
+import org.eclipse.core.runtime.IProduct;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.OperationCanceledException;
 import org.eclipse.core.runtime.Platform;
 import org.eclipse.core.runtime.Status;
 import org.eclipse.core.runtime.jobs.Job;
 import org.eclipse.core.runtime.preferences.ConfigurationScope;
+import org.eclipse.core.runtime.preferences.IEclipsePreferences;
+import org.eclipse.core.runtime.preferences.UserScope;
 import org.eclipse.equinox.app.IApplication;
 import org.eclipse.equinox.app.IApplicationContext;
 import org.eclipse.jface.dialogs.IDialogConstants;
@@ -52,14 +55,18 @@
 import org.eclipse.osgi.service.datalocation.Location;
 import org.eclipse.osgi.util.NLS;
 import org.eclipse.swt.SWT;
+import org.eclipse.swt.graphics.Color;
 import org.eclipse.swt.layout.FillLayout;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Control;
 import org.eclipse.swt.widgets.Display;
 import org.eclipse.swt.widgets.Label;
+import org.eclipse.swt.widgets.Link;
+import org.eclipse.swt.widgets.Listener;
 import org.eclipse.swt.widgets.Shell;
 import org.eclipse.ui.IWorkbench;
 import org.eclipse.ui.PlatformUI;
+import org.eclipse.ui.forms.widgets.ExpandableComposite;
 import org.eclipse.ui.internal.Workbench;
 import org.eclipse.ui.internal.WorkbenchPlugin;
 import org.eclipse.ui.internal.WorkspaceLock;
@@ -94,6 +101,9 @@ public class IDEApplication implements IApplication, IExecutableExtension {
 
 	private static final String USER_NAME = "user.name"; //$NON-NLS-1$
 
+	private boolean isDark;
+	private Listener darkThemeShowListener;
+
 	// Use the branding plug-in of the platform feature since this is most likely
 	// to change on an update of the IDE.
 	private static final String WORKSPACE_CHECK_REFERENCE_BUNDLE_NAME = "org.eclipse.platform"; //$NON-NLS-1$
@@ -145,6 +155,9 @@ public Object start(IApplicationContext appContext) throws Exception {
 		Job.getJobManager().suspend();
 
 		Display display = createDisplay();
+
+		initializeDefaultTheme(display);
+
 		// processor must be created before we start event loop
 		DelayedEventsProcessor processor = new DelayedEventsProcessor(display);
 
@@ -167,6 +180,10 @@ public Object start(IApplicationContext appContext) throws Exception {
 				return instanceLocationCheck;
 			}
 
+			// Reset early dark theme styling before the workbench starts;
+			// the ThemeEngine will apply the correct theme from here on.
+			resetEarlyDarkTheme(display);
+
 			// create the workbench with this advisor and run it until it exits
 			// N.B. createWorkbench remembers the advisor, and also registers
 			// the workbench globally so that all UI plug-ins can find it using
@@ -587,6 +604,14 @@ protected Shell getParentShell() {
 				return null;
 			}
 
+			@Override
+			protected Control createContents(Composite parent) {
+				Control contents = super.createContents(parent);
+				if (isDark) {
+					applyDarkStyles(getShell());
+				}
+				return contents;
+			}
 		}.prompt(force);
 	}
 
@@ -852,6 +877,90 @@ protected static Version toMajorMinorVersion(Version version) {
 		return new Version(version.getMajor(), version.getMinor(), 0);
 	}
 
+	protected void initializeDefaultTheme(Display display) {
+		IEclipsePreferences themeNode = UserScope.INSTANCE.getNode("org.eclipse.e4.ui.css.swt.theme"); //$NON-NLS-1$
+		String productOrAppId = getProductOrApplicationId();
+		String defaultThemeId = null;
+		if (productOrAppId != null) {
+			defaultThemeId = themeNode.node(productOrAppId).get("themeid", null); //$NON-NLS-1$
+		}
+		if (defaultThemeId == null) {
+			defaultThemeId = themeNode.get("themeid", null); //$NON-NLS-1$
+		}
+		isDark = defaultThemeId != null && defaultThemeId.contains("dark"); //$NON-NLS-1$
+		if (isDark) {
+			display.setDarkThemePreferred(true);
+			darkThemeShowListener = event -> {
+				if (event.widget instanceof Shell shell) {
+					applyDarkStyles(shell);
+				}
+			};
+			display.addListener(SWT.Show, darkThemeShowListener);
+		}
+	}
+
+	/**
+	 * Removes the early dark theme styling applied for the workspace selection
+	 * dialog. Must be called before the workbench starts so the ThemeEngine can
+	 * manage the theme without interference.
+	 */
+	protected void resetEarlyDarkTheme(Display display) {
+		if (darkThemeShowListener != null) {
+			display.removeListener(SWT.Show, darkThemeShowListener);
+			darkThemeShowListener = null;
+		}
+		if (isDark) {
+			display.setDarkThemePreferred(false);
+		}
+	}
+
+	/**
+	 * Returns the product ID if a product is configured, otherwise falls back to
+	 * the application ID from the system property. Returns {@code null} if neither
+	 * is available.
+	 */
+	private static String getProductOrApplicationId() {
+		IProduct product = Platform.getProduct();
+		if (product != null) {
+			return product.getId();
+		}
+		return System.getProperty("eclipse.application"); //$NON-NLS-1$
+	}
+
+	private void applyDarkStyles(Shell shell) {
+		Color bg = new Color(shell.getDisplay(), 72, 72, 76); // #48484c
+		Color fg = new Color(shell.getDisplay(), 238, 238, 238); // #eeeeee
+		Color linkColor = new Color(shell.getDisplay(), 111, 197, 238); // #6FC5EE
+		shell.setBackground(bg);
+		shell.setForeground(fg);
+		applyStylesRecursive(shell, bg, fg, linkColor);
+		shell.addDisposeListener(e -> {
+			bg.dispose();
+			fg.dispose();
+		});
+	}
+
+	private 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 ExpandableComposite expandable) {
+			expandable.setTitleBarForeground(fg);
+			expandable.setToggleColor(fg);
+			expandable.setActiveToggleColor(fg);
+		}
+		if (control instanceof Composite composite) {
+			for (Control child : composite.getChildren()) {
+				applyStylesRecursive(child, bg, fg, linkColor);
+			}
+		}
+	}
+
 	@Override
 	public void stop() {
 		final IWorkbench workbench = PlatformUI.getWorkbench();

bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/ChooseWorkspaceDialog.java

@@ -39,6 +39,7 @@
 import org.eclipse.jface.dialogs.IDialogConstants;
 import org.eclipse.jface.dialogs.IDialogSettings;
 import org.eclipse.jface.dialogs.TitleAreaDialog;
+import org.eclipse.jface.resource.JFaceColors;
 import org.eclipse.jface.util.Geometry;
 import org.eclipse.jface.window.Window;
 import org.eclipse.osgi.util.NLS;
@@ -319,6 +320,10 @@ private void createRecentWorkspacesComposite(final Composite composite) {
 		recentWorkspacesForm.getBody().setLayout(new GridLayout());
 		ExpandableComposite recentWorkspacesExpandable = toolkit.createExpandableComposite(recentWorkspacesForm.getBody(),
 				ExpandableComposite.TWISTIE);
+		recentWorkspacesExpandable.setTitleBarForeground(composite.getForeground());
+		recentWorkspacesExpandable.setForeground(composite.getForeground());
+		recentWorkspacesExpandable.setToggleColor(composite.getForeground());
+		recentWorkspacesExpandable.setActiveToggleColor(composite.getForeground());
 		recentWorkspacesForm.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));
 		recentWorkspacesExpandable.setBackground(composite.getBackground());
 		recentWorkspacesExpandable.setText(IDEWorkbenchMessages.ChooseWorkspaceDialog_recentWorkspaces);
@@ -352,6 +357,7 @@ public void expansionStateChanged(ExpansionEvent e) {
 			final String recentWorkspace = uniqueWorkspaceEntry.getValue();
 
 			Link link = new Link(panel, SWT.WRAP);
+			link.setForeground(JFaceColors.getHyperlinkText(composite.getDisplay()));
 			link.setLayoutData(new RowData(SWT.DEFAULT, SWT.DEFAULT));
 			link.setText("<a>" + uniqueWorkspaceEntry.getKey() + "</a>"); //$NON-NLS-1$ //$NON-NLS-2$
 			link.setToolTipText(recentWorkspace);

bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/ChooseWorkspaceWithSettingsDialog.java

@@ -128,6 +128,9 @@ private void createSettingsControls(Composite workArea) {
 
 		copySettingsExpandable.setText(IDEWorkbenchMessages.ChooseWorkspaceWithSettingsDialog_SettingsGroupName);
 		copySettingsExpandable.setBackground(workArea.getBackground());
+		copySettingsExpandable.setTitleBarForeground(workArea.getForeground());
+		copySettingsExpandable.setToggleColor(workArea.getForeground());
+		copySettingsExpandable.setActiveToggleColor(workArea.getForeground());
 		copySettingsExpandable.setLayout(new GridLayout());
 		copySettingsExpandable.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));
 		copySettingsExpandable.addExpansionListener(new IExpansionListener() {