Add dirty indicator bullet style for CTabFolder tabs

When enabled via CTabFolder.setDirtyIndicatorCloseStyle(true), dirty
tabs show a filled circle at the close button location instead of the
traditional '*' prefix. The bullet transforms into the close button on
hover, matching the behavior of VS Code and similar editors.

This is opt-in (disabled by default) to preserve backward compatibility.
The feature adds:
- CTabFolder.setDirtyIndicatorCloseStyle(boolean) / getDirtyIndicatorCloseStyle()
- CTabItem.setShowDirty(boolean) / getShowDirty()
- Rendering via fillOval for cross-platform consistency
- Snippet391 demonstrating the feature

Based on the approach from PR #1632 by schneidermic0, with fixes for
the copy-paste bug, preference toggle support per PMC request, and
fillOval rendering instead of drawString for pixel-perfect results.

See: #1632

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: vogella

bundles/org.eclipse.swt/Eclipse SWT Custom Widgets/common/org/eclipse/swt/custom/CTabFolder.java

@@ -200,6 +200,7 @@ public class CTabFolder extends Composite {
 	// close, min/max and chevron buttons
 	boolean showClose = false;
 	boolean showUnselectedClose = true;
+	boolean dirtyIndicatorStyle = false;
 
 	boolean showMin = false;
 	boolean minimized = false;
@@ -2794,7 +2795,7 @@ boolean setItemLocation(GC gc) {
 				item.x = leftItemEdge;
 				item.y = y;
 				item.showing = true;
-				if (showClose || item.showClose) {
+				if (showClose || item.showClose || (dirtyIndicatorStyle && item.showDirty)) {
 					item.closeRect.x = leftItemEdge - renderer.computeTrim(i, SWT.NONE, 0, 0, 0, 0).x;
 					item.closeRect.y = onBottom ? size.y - borderBottom - tabHeight + (tabHeight - closeButtonSize.y)/2: borderTop + (tabHeight - closeButtonSize.y)/2;
 				}
@@ -2896,7 +2897,7 @@ boolean setItemSize(GC gc) {
 				tab.height = tabHeight;
 				tab.width = width;
 				tab.closeRect.width = tab.closeRect.height = 0;
-				if (showClose || tab.showClose) {
+				if (showClose || tab.showClose || (dirtyIndicatorStyle && tab.showDirty)) {
 					Point closeSize = renderer.computeSize(CTabFolderRenderer.PART_CLOSE_BUTTON, SWT.SELECTED, gc, SWT.DEFAULT, SWT.DEFAULT);
 					tab.closeRect.width = closeSize.x;
 					tab.closeRect.height = closeSize.y;
@@ -2980,7 +2981,7 @@ boolean setItemSize(GC gc) {
 		tab.height = tabHeight;
 		tab.width = width;
 		tab.closeRect.width = tab.closeRect.height = 0;
-		if (showClose || tab.showClose) {
+		if (showClose || tab.showClose || (dirtyIndicatorStyle && tab.showDirty)) {
 			if (i == selectedIndex || showUnselectedClose) {
 				Point closeSize = renderer.computeSize(CTabFolderRenderer.PART_CLOSE_BUTTON, SWT.NONE, gc, SWT.DEFAULT, SWT.DEFAULT);
 				tab.closeRect.width = closeSize.x;
@@ -3687,6 +3688,50 @@ public void setUnselectedCloseVisible(boolean visible) {
 	showUnselectedClose = visible;
 	updateFolder(REDRAW);
 }
+/**
+ * Sets whether the dirty indicator uses the close button style. When enabled,
+ * dirty items (marked via {@link CTabItem#setShowDirty(boolean)}) show a
+ * bullet dot at the close button location instead of the traditional
+ * <code>*</code> prefix. The bullet transforms into the close button on hover.
+ * <p>
+ * The default value is <code>false</code> (traditional <code>*</code> prefix
+ * behavior).
+ * </p>
+ *
+ * @param useCloseButtonStyle <code>true</code> to use the bullet-on-close-button
+ *        style for dirty indicators
+ *
+ * @exception SWTException <ul>
+ *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
+ *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
+ * </ul>
+ *
+ * @see CTabItem#setShowDirty(boolean)
+ * @since 3.133
+ */
+public void setDirtyIndicatorCloseStyle(boolean useCloseButtonStyle) {
+	checkWidget();
+	if (dirtyIndicatorStyle == useCloseButtonStyle) return;
+	dirtyIndicatorStyle = useCloseButtonStyle;
+	updateFolder(REDRAW_TABS);
+}
+/**
+ * Returns whether the dirty indicator uses the close button style.
+ *
+ * @return <code>true</code> if the dirty indicator uses the close button style
+ *
+ * @exception SWTException <ul>
+ *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
+ *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
+ * </ul>
+ *
+ * @see #setDirtyIndicatorCloseStyle(boolean)
+ * @since 3.133
+ */
+public boolean getDirtyIndicatorCloseStyle() {
+	checkWidget();
+	return dirtyIndicatorStyle;
+}
 /**
  * Specify whether the image appears on unselected tabs.
  *
@@ -4021,7 +4066,7 @@ String _getToolTip(int x, int y) {
 	CTabItem item = getItem(new Point (x, y));
 	if (item == null) return null;
 	if (!item.showing) return null;
-	if ((showClose || item.showClose) && item.closeRect.contains(x, y)) {
+	if ((showClose || item.showClose || (dirtyIndicatorStyle && item.showDirty)) && item.closeRect.contains(x, y)) {
 		return SWT.getMessage("SWT_Close"); //$NON-NLS-1$
 	}
 	return item.getToolTipText();

bundles/org.eclipse.swt/Eclipse SWT Custom Widgets/common/org/eclipse/swt/custom/CTabFolderRenderer.java

@@ -363,7 +363,7 @@ protected Point computeSize (int part, int state, GC gc, int wHint, int hHint) {
 
 					if (shouldApplyLargeTextPadding(parent)) {
 						width += getLargeTextPadding(item) * 2;
-					} else if (shouldDrawCloseIcon(item)) {
+					} else if (shouldAllocateCloseRect(item)) {
 						if (width > 0) width += INTERNAL_SPACING;
 						width += computeSize(PART_CLOSE_BUTTON, SWT.NONE, gc, SWT.DEFAULT, SWT.DEFAULT).x;
 					}
@@ -383,6 +383,16 @@ private boolean shouldDrawCloseIcon(CTabItem item) {
 		return showClose && isSelectedOrShowCloseForUnselected;
 	}
 
+	private boolean shouldDrawDirtyIndicator(CTabItem item) {
+		CTabFolder folder = item.getParent();
+		if (!folder.dirtyIndicatorStyle || !item.showDirty) return false;
+		return (item.state & SWT.SELECTED) != 0 || folder.showUnselectedClose;
+	}
+
+	private boolean shouldAllocateCloseRect(CTabItem item) {
+		return shouldDrawCloseIcon(item) || shouldDrawDirtyIndicator(item);
+	}
+
 	/**
 	 * Returns padding for the text of a tab item when showing images is disabled for the tab folder.
 	 */
@@ -880,8 +890,21 @@ void drawBody(GC gc, Rectangle bounds, int state) {
 	}
 
 	void drawClose(GC gc, Rectangle closeRect, int closeImageState) {
+		drawClose(gc, closeRect, closeImageState, false);
+	}
+
+	void drawClose(GC gc, Rectangle closeRect, int closeImageState, boolean showDirtyIndicator) {
 		if (closeRect.width == 0 || closeRect.height == 0) return;
 
+		// When dirty and not hovered/pressed, draw bullet instead of X
+		if (showDirtyIndicator) {
+			int maskedState = closeImageState & (SWT.HOT | SWT.SELECTED | SWT.BACKGROUND);
+			if (maskedState != SWT.HOT && maskedState != SWT.SELECTED) {
+				drawDirtyIndicator(gc, closeRect);
+				return;
+			}
+		}
+
 		// draw X with length of this constant
 		final int lineLength = 8;
 		int x = closeRect.x + Math.max(1, (closeRect.width-lineLength)/2);
@@ -912,6 +935,17 @@ void drawClose(GC gc, Rectangle closeRect, int closeImageState) {
 		gc.setForeground(originalForeground);
 	}
 
+	private void drawDirtyIndicator(GC gc, Rectangle closeRect) {
+		int diameter = 8;
+		int x = closeRect.x + (closeRect.width - diameter) / 2;
+		int y = closeRect.y + (closeRect.height - diameter) / 2;
+		y += parent.onBottom ? -1 : 1;
+		Color originalBackground = gc.getBackground();
+		gc.setBackground(gc.getForeground());
+		gc.fillOval(x, y, diameter, diameter);
+		gc.setBackground(originalBackground);
+	}
+
 	private void drawCloseLines(GC gc, int x, int y, int lineLength, boolean hot) {
 		if (hot) {
 			gc.setLineWidth(gc.getLineWidth() + 2);
@@ -1420,7 +1454,7 @@ void drawSelected(int itemIndex, GC gc, Rectangle bounds, int state ) {
 			// draw Image
 			Rectangle trim = computeTrim(itemIndex, SWT.NONE, 0, 0, 0, 0);
 			int xDraw = x - trim.x;
-			if (parent.single && shouldDrawCloseIcon(item)) xDraw += item.closeRect.width;
+			if (parent.single && shouldAllocateCloseRect(item)) xDraw += item.closeRect.width;
 			Image image = item.getImage();
 			if (image != null && !image.isDisposed() && parent.showSelectedImage) {
 				Rectangle imageBounds = image.getBounds();
@@ -1473,15 +1507,17 @@ void drawSelected(int itemIndex, GC gc, Rectangle bounds, int state ) {
 					gc.setBackground(orginalBackground);
 				}
 			}
-			if (shouldDrawCloseIcon(item)) drawClose(gc, item.closeRect, item.closeImageState);
+			if (shouldAllocateCloseRect(item)) {
+				drawClose(gc, item.closeRect, item.closeImageState, shouldDrawDirtyIndicator(item) && !shouldDrawCloseIcon(item));
+			}
 		}
 	}
 
 	private int getLeftTextMargin(CTabItem item) {
 		int margin = 0;
 		if (shouldApplyLargeTextPadding(parent)) {
 			margin += getLargeTextPadding(item);
-			if (shouldDrawCloseIcon(item)) {
+			if (shouldAllocateCloseRect(item)) {
 				 margin -= item.closeRect.width / 2;
 			}
 		}
@@ -1646,7 +1682,7 @@ void drawUnselected(int index, GC gc, Rectangle bounds, int state) {
 				Rectangle imageBounds = image.getBounds();
 				// only draw image if it won't overlap with close button
 				int maxImageWidth = x + width - xDraw - (trim.width + trim.x);
-				if (shouldDrawCloseIcon(item)) {
+				if (shouldAllocateCloseRect(item)) {
 					maxImageWidth -= item.closeRect.width + INTERNAL_SPACING;
 				}
 				if (imageBounds.width < maxImageWidth) {
@@ -1662,7 +1698,7 @@ void drawUnselected(int index, GC gc, Rectangle bounds, int state) {
 			// draw Text
 			xDraw += getLeftTextMargin(item);
 			int textWidth = x + width - xDraw - (trim.width + trim.x);
-			if (shouldDrawCloseIcon(item)) {
+			if (shouldAllocateCloseRect(item)) {
 				textWidth -= item.closeRect.width + INTERNAL_SPACING;
 			}
 			if (textWidth > 0) {
@@ -1679,8 +1715,10 @@ void drawUnselected(int index, GC gc, Rectangle bounds, int state) {
 				gc.drawText(item.shortenedText, xDraw, textY, FLAGS);
 				gc.setFont(gcFont);
 			}
-			// draw close
-			if (shouldDrawCloseIcon(item)) drawClose(gc, item.closeRect, item.closeImageState);
+			// draw close or dirty indicator
+			if (shouldAllocateCloseRect(item)) {
+				drawClose(gc, item.closeRect, item.closeImageState, shouldDrawDirtyIndicator(item) && !shouldDrawCloseIcon(item));
+			}
 		}
 	}
 

bundles/org.eclipse.swt/Eclipse SWT Custom Widgets/common/org/eclipse/swt/custom/CTabItem.java

@@ -55,6 +55,7 @@ public class CTabItem extends Item {
 	int closeImageState = SWT.BACKGROUND;
 	int state = SWT.NONE;
 	boolean showClose = false;
+	boolean showDirty = false;
 	boolean showing = false;
 
 /**
@@ -276,6 +277,26 @@ public boolean getShowClose() {
 	checkWidget();
 	return showClose;
 }
+/**
+ * Returns <code>true</code> to indicate that the receiver is dirty
+ * (has unsaved changes). When the parent folder's dirty indicator style
+ * is enabled, dirty items show a bullet dot at the close button location
+ * instead of the default <code>*</code> prefix.
+ *
+ * @return <code>true</code> if the item is marked as dirty
+ *
+ * @exception SWTException <ul>
+ *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
+ *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
+ * </ul>
+ *
+ * @see CTabFolder#setDirtyIndicatorCloseStyle(boolean)
+ * @since 3.133
+ */
+public boolean getShowDirty() {
+	checkWidget();
+	return showDirty;
+}
 /**
  * Returns the receiver's tool tip text, or null if it has
  * not been set.
@@ -490,6 +511,29 @@ public void setShowClose(boolean close) {
 	showClose = close;
 	parent.updateFolder(CTabFolder.REDRAW_TABS);
 }
+/**
+ * Marks this item as dirty (having unsaved changes). When the parent
+ * folder's dirty indicator style is enabled via
+ * {@link CTabFolder#setDirtyIndicatorCloseStyle(boolean)}, dirty items
+ * show a bullet dot at the close button location. The bullet transforms
+ * into the close button on hover.
+ *
+ * @param dirty <code>true</code> to mark the item as dirty
+ *
+ * @exception SWTException <ul>
+ *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
+ *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
+ * </ul>
+ *
+ * @see CTabFolder#setDirtyIndicatorCloseStyle(boolean)
+ * @since 3.133
+ */
+public void setShowDirty(boolean dirty) {
+	checkWidget();
+	if (showDirty == dirty) return;
+	showDirty = dirty;
+	parent.updateFolder(CTabFolder.REDRAW_TABS);
+}
 /**
  * Sets the text to display on the tab.
  * A carriage return '\n' allows to display multi line text.

examples/org.eclipse.swt.snippets/src/org/eclipse/swt/snippets/Snippet393.java

@@ -0,0 +1,66 @@
+/*******************************************************************************
+ * Copyright (c) 2026 Contributors to the Eclipse Foundation
+ *
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *******************************************************************************/
+package org.eclipse.swt.snippets;
+
+/*
+ * CTabFolder example: dirty indicator using bullet dot on close button
+ *
+ * For a list of all SWT example snippets see
+ * http://www.eclipse.org/swt/snippets/
+ */
+import org.eclipse.swt.*;
+import org.eclipse.swt.custom.*;
+import org.eclipse.swt.layout.*;
+import org.eclipse.swt.widgets.*;
+
+public class Snippet393 {
+	public static void main(String[] args) {
+		Display display = new Display();
+		Shell shell = new Shell(display);
+		shell.setLayout(new GridLayout());
+		shell.setText("CTabFolder Dirty Indicator");
+
+		CTabFolder folder = new CTabFolder(shell, SWT.CLOSE | SWT.BORDER);
+		folder.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
+		folder.setDirtyIndicatorCloseStyle(true);
+
+		for (int i = 0; i < 4; i++) {
+			CTabItem item = new CTabItem(folder, SWT.NONE);
+			item.setText("Tab " + i);
+			Text text = new Text(folder, SWT.MULTI | SWT.WRAP);
+			text.setText("Content for tab " + i);
+			item.setControl(text);
+		}
+
+		// Mark tabs 0 and 2 as dirty
+		folder.getItem(0).setShowDirty(true);
+		folder.getItem(2).setShowDirty(true);
+		folder.setSelection(0);
+
+		Button toggleButton = new Button(shell, SWT.PUSH);
+		toggleButton.setText("Toggle dirty on selected tab");
+		toggleButton.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true, false));
+		toggleButton.addListener(SWT.Selection, e -> {
+			CTabItem selected = folder.getSelection();
+			if (selected != null) {
+				selected.setShowDirty(!selected.getShowDirty());
+			}
+		});
+
+		shell.setSize(400, 300);
+		shell.open();
+		while (!shell.isDisposed()) {
+			if (!display.readAndDispatch())
+				display.sleep();
+		}
+		display.dispose();
+	}
+}

tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/Test_org_eclipse_swt_custom_CTabItem.java

@@ -14,6 +14,8 @@
 package org.eclipse.swt.tests.junit;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.custom.CTabFolder;
@@ -76,4 +78,22 @@ public void test_setSelectionForegroundLorg_eclipse_swt_graphics_Color() {
 	cTabItem.setSelectionForeground(null);
 	assertEquals(red, cTabItem.getSelectionForeground());
 }
+
+@Test
+public void test_setShowDirty() {
+	assertFalse(cTabItem.getShowDirty());
+	cTabItem.setShowDirty(true);
+	assertTrue(cTabItem.getShowDirty());
+	cTabItem.setShowDirty(false);
+	assertFalse(cTabItem.getShowDirty());
+}
+
+@Test
+public void test_dirtyIndicatorCloseStyle() {
+	assertFalse(cTabFolder.getDirtyIndicatorCloseStyle());
+	cTabFolder.setDirtyIndicatorCloseStyle(true);
+	assertTrue(cTabFolder.getDirtyIndicatorCloseStyle());
+	cTabFolder.setDirtyIndicatorCloseStyle(false);
+	assertFalse(cTabFolder.getDirtyIndicatorCloseStyle());
+}
 }