Added dynamic tab alignment support in MultiPageEditorPart

bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/dialogs/IDEEditorsPreferencePage.java

@@ -62,6 +62,7 @@ protected Control createContents(Composite parent) {
 		createUseIPersistablePref(composite);
 		createPromptWhenStillOpenPref(composite);
 		createEditorReuseGroup(composite);
+		createAlignMultiPageEditorTabs(composite);
 
 		applyDialogFont(composite);
 

bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/IWorkbenchPreferenceConstants.java

@@ -624,6 +624,20 @@ public interface IWorkbenchPreferenceConstants {
 	 */
 	String DISABLE_OPEN_EDITOR_IN_PLACE = "DISABLE_OPEN_EDITOR_IN_PLACE"; //$NON-NLS-1$
 
+	/**
+	 * Workbench preference id for the position of the tabs in the multi-page
+	 * editor.
+	 *
+	 * Integer-valued: {@link SWT#TOP} for tabs on the top, and {@link SWT#BOTTOM}
+	 * for tabs at the bottom.
+	 * <p>
+	 * The default value for this preference is: {@link SWT#BOTTOM}
+	 * </p>
+	 *
+	 * @since 3.133
+	 */
+	String ALIGN_MULTI_PAGE_EDITOR_TABS = "ALIGN_MULTI_PAGE_EDITOR_TABS"; //$NON-NLS-1$
+
 	/**
 	 * Workbench preference id for indicating the size of the list of most recently
 	 * used working sets.

bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/WorkbenchMessages.java

@@ -452,6 +452,9 @@ public class WorkbenchMessages extends NLS {
 	public static String WorkbenchPreference_stickyCycleButton;
 	public static String WorkbenchPreference_RunInBackgroundButton;
 	public static String WorkbenchPreference_RunInBackgroundToolTip;
+	public static String WorkbenchPreference_AlignMultiPageEditorTabs;
+	public static String WorkbenchPreference_AlignMultiPageEditorTabs_Top;
+	public static String WorkbenchPreference_AlignMultiPageEditorTabs_Bottom;
 
 	// --- Appearance ---
 	public static String ViewsPreferencePage_Theme;

bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/WorkbenchPreferenceInitializer.java

@@ -102,6 +102,7 @@ public void initializeDefaultPreferences() {
 		// Heap status preferences is stored in different node
 		IEclipsePreferences heapNode = context.getNode("org.eclipse.ui"); //$NON-NLS-1$
 		heapNode.putBoolean(IWorkbenchPreferenceConstants.SHOW_MEMORY_MONITOR, false);
+		heapNode.putInt(IWorkbenchPreferenceConstants.ALIGN_MULTI_PAGE_EDITOR_TABS, SWT.BOTTOM);
 		node.putInt(IHeapStatusConstants.PREF_UPDATE_INTERVAL, 500);
 		node.putBoolean(IHeapStatusConstants.PREF_SHOW_MAX, false);
 		node.putBoolean(IPreferenceConstants.OVERRIDE_PRESENTATION, false);

bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/dialogs/EditorsPreferencePage.java

@@ -18,6 +18,10 @@
 
 import static org.eclipse.swt.events.SelectionListener.widgetSelectedAdapter;
 
+import org.eclipse.jface.action.Action;
+import org.eclipse.jface.layout.GridDataFactory;
+import org.eclipse.jface.layout.GridLayoutFactory;
+import org.eclipse.jface.preference.ComboFieldEditor;
 import org.eclipse.jface.preference.FieldEditor;
 import org.eclipse.jface.preference.IPreferenceStore;
 import org.eclipse.jface.preference.IntegerFieldEditor;
@@ -72,6 +76,8 @@ public class EditorsPreferencePage extends PreferencePage implements IWorkbenchP
 
 	private Button allowInplaceEditor;
 
+	private ComboFieldEditor multiPageEditorTabPositionComboField;
+
 	@Override
 	protected Control createContents(Composite parent) {
 		Composite composite = createComposite(parent);
@@ -130,6 +136,23 @@ protected void createPromptWhenStillOpenPref(Composite composite) {
 		setButtonLayoutData(promptWhenStillOpenEditor);
 	}
 
+	protected void createAlignMultiPageEditorTabs(Composite parent) {
+		Composite comboComposite = new Composite(parent, SWT.NONE);
+		comboComposite.setLayout(GridLayoutFactory.fillDefaults().numColumns(2).create());
+		comboComposite.setLayoutData(GridDataFactory.fillDefaults().create());
+		String name = IWorkbenchPreferenceConstants.ALIGN_MULTI_PAGE_EDITOR_TABS;
+		String label = WorkbenchMessages.WorkbenchPreference_AlignMultiPageEditorTabs;
+		String[][] namesAndValues = {
+				{ Action.removeMnemonics(WorkbenchMessages.WorkbenchPreference_AlignMultiPageEditorTabs_Top),
+						String.valueOf(SWT.TOP) },
+				{ Action.removeMnemonics(WorkbenchMessages.WorkbenchPreference_AlignMultiPageEditorTabs_Bottom),
+						String.valueOf(SWT.BOTTOM) } };
+		multiPageEditorTabPositionComboField = new ComboFieldEditor(name, label, namesAndValues, comboComposite);
+		multiPageEditorTabPositionComboField.setPreferenceStore(getAPIPreferenceStore());
+		multiPageEditorTabPositionComboField.setPage(this);
+		multiPageEditorTabPositionComboField.load();
+	}
+
 	protected Composite createComposite(Composite parent) {
 		Composite composite = new Composite(parent, SWT.NULL);
 		GridLayout layout = new GridLayout();
@@ -158,11 +181,13 @@ protected void performDefaults() {
 		reuseEditorsThreshold.getLabelControl(editorReuseThresholdGroup).setEnabled(reuseEditors.getSelection());
 		reuseEditorsThreshold.getTextControl(editorReuseThresholdGroup).setEnabled(reuseEditors.getSelection());
 		recentFilesEditor.loadDefault();
+		multiPageEditorTabPositionComboField.loadDefault();
 	}
 
 	@Override
 	public boolean performOk() {
 		IPreferenceStore store = getPreferenceStore();
+		multiPageEditorTabPositionComboField.store();
 		getAPIPreferenceStore().setValue(IWorkbenchPreferenceConstants.DISABLE_OPEN_EDITOR_IN_PLACE,
 				!allowInplaceEditor.getSelection());
 		store.setValue(IPreferenceConstants.USE_IPERSISTABLE_EDITORS, useIPersistableEditor.getSelection());

bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/messages.properties

@@ -419,6 +419,9 @@ WorkbenchPreference_RunInBackgroundButton=Always r&un in background
 WorkbenchPreference_RunInBackgroundToolTip=Run long operations in the background where possible
 WorkbenchPreference_HeapStatusButton = Sho&w heap status
 WorkbenchPreference_HeapStatusButtonToolTip = Show the heap status area on the bottom of the window
+WorkbenchPreference_AlignMultiPageEditorTabs= &Align multi-page editor tabs:
+WorkbenchPreference_AlignMultiPageEditorTabs_Top= &Top
+WorkbenchPreference_AlignMultiPageEditorTabs_Bottom= &Bottom
 
 
 # --- Appearance ---
@@ -493,10 +496,10 @@ OpenPerspectiveDialogAction_tooltip=Open Perspective
 
 #---- General Preferences----
 PreferencePage_noDescription = (No description available)
-PreferencePageParameterValues_pageLabelSeparator = \ >\ 
+PreferencePageParameterValues_pageLabelSeparator = \ >\
 ThemingEnabled = E&nable theming
 ThemeChangeWarningText = Restart for the theme changes to take full effect
-ThemeChangeWarningTitle = Theme Changed 
+ThemeChangeWarningTitle = Theme Changed
 # --- Workbench -----
 WorkbenchPreference_openMode=Open mode
 WorkbenchPreference_doubleClick=D&ouble click

bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/part/MultiPageEditorPart.java

@@ -17,6 +17,7 @@
 
 import static org.eclipse.swt.events.SelectionListener.widgetSelectedAdapter;
 
+import java.beans.PropertyChangeListener;
 import java.util.ArrayList;
 import java.util.List;
 import org.eclipse.core.commands.AbstractHandler;
@@ -32,7 +33,9 @@
 import org.eclipse.jface.dialogs.IPageChangeProvider;
 import org.eclipse.jface.dialogs.IPageChangedListener;
 import org.eclipse.jface.dialogs.PageChangedEvent;
+import org.eclipse.jface.preference.IPreferenceStore;
 import org.eclipse.jface.resource.ImageDescriptor;
+import org.eclipse.jface.util.PropertyChangeEvent;
 import org.eclipse.jface.util.SafeRunnable;
 import org.eclipse.jface.viewers.ISelectionProvider;
 import org.eclipse.jface.viewers.SelectionChangedEvent;
@@ -56,13 +59,15 @@
 import org.eclipse.ui.IPartService;
 import org.eclipse.ui.IWorkbenchPart;
 import org.eclipse.ui.IWorkbenchPartSite;
+import org.eclipse.ui.IWorkbenchPreferenceConstants;
 import org.eclipse.ui.PartInitException;
 import org.eclipse.ui.handlers.IHandlerService;
 import org.eclipse.ui.internal.PartSite;
 import org.eclipse.ui.internal.WorkbenchPlugin;
 import org.eclipse.ui.internal.misc.Policy;
 import org.eclipse.ui.internal.services.INestable;
 import org.eclipse.ui.internal.services.IServiceLocatorCreator;
+import org.eclipse.ui.internal.util.PrefUtil;
 import org.eclipse.ui.services.IDisposable;
 import org.eclipse.ui.services.IServiceLocator;
 
@@ -149,10 +154,31 @@
 	private ListenerList<IPageChangedListener> pageChangeListeners = new ListenerList<>(ListenerList.IDENTITY);
 
 	/**
-	 * Creates an empty multi-page editor with no pages.
+	 * Creates an empty multi-page editor with no pages and registers a
+	 * {@link PropertyChangeListener} to listen for changes to the editor's
+	 * preference..
 	 */
 	protected MultiPageEditorPart() {
 		super();
+		getAPIPreferenceStore().addPropertyChangeListener(event -> {
+			if (isUpdateRequired(event)) {
+				updateContainer();
+			}
+		});
+	}
+
+	/**
+	 * Determines whether an update is required based on a property change event.
+	 *
+	 * @param event the {@link PropertyChangeEvent} triggered by a change in the
+	 *              preference store
+	 * @since 3.133
+	 */
+	protected boolean isUpdateRequired(PropertyChangeEvent event) {
+		if (event.getProperty().equals(IWorkbenchPreferenceConstants.ALIGN_MULTI_PAGE_EDITOR_TABS)) {
+			return true;
+		}
+		return false;
 	}
 
 	/**
@@ -264,7 +290,7 @@
 		// use SWT.FLAT style so that an extra 1 pixel border is not reserved
 		// inside the folder
 		parent.setLayout(new FillLayout());
-		final CTabFolder newContainer = new CTabFolder(parent, SWT.BOTTOM | SWT.FLAT);
+		final CTabFolder newContainer = new CTabFolder(parent, getTabStyle() | SWT.FLAT);
 		newContainer.addSelectionListener(widgetSelectedAdapter(e -> {
 			int newPageIndex = newContainer.indexOf((CTabItem) e.item);
 			pageChange(newPageIndex);
@@ -291,6 +317,29 @@
 		return newContainer;
 	}
 
+	/**
+	 * Determines the tab style based on user preferences.
+	 * <p>
+	 * This method retrieves the user preference for aligning multi-page editor tabs
+	 * on top or bottom, and returns the corresponding SWT style constant.
+	 * </p>
+	 *
+	 * @return {@code SWT.TOP} if the user prefers tabs to be aligned on top,
+	 *         {@code SWT.BOTTOM} if the user prefers tabs to be aligned on the
+	 *         bottom.
+	 * @since 3.133
+	 */
+	protected int getTabStyle() {
+		return getAPIPreferenceStore().getInt(IWorkbenchPreferenceConstants.ALIGN_MULTI_PAGE_EDITOR_TABS);
+	}
+
+	/**
+	 * @since 3.133
+	 */
+	protected IPreferenceStore getAPIPreferenceStore() {
+		return PrefUtil.getAPIPreferenceStore();
+	}
+
 	/**
 	 * Creates a tab item at the given index and places the given control in the new
 	 * item. The item is a CTabItem with no style bits set.
@@ -915,8 +964,8 @@
 
 		if (editor != null) {
 			// active the service for this inner editor
 			if (service instanceof INestableKeyBindingService) {
 				final INestableKeyBindingService nestableService = (INestableKeyBindingService) service;
 				nestableService.activateKeyBindingService(editor.getEditorSite());
 
 			} else {
@@ -1230,4 +1279,23 @@
 			});
 		}
 	}
+
+	/**
+	 * Updates the tab position of the container in the multi-page editor.
+	 *
+	 * <p>
+	 * This method retrieves the current container and sets the tab position based
+	 * on the user preference.
+	 * </p>
+	 *
+	 * @since 3.133
+	 */
+	protected void updateContainer() {
+		Composite container = getContainer();
+		if (container instanceof CTabFolder tabFolder) {
+			tabFolder.setTabPosition(getTabStyle());
+			tabFolder.requestLayout();
+		}
+	}
+
 }