Fix sticky scroll height calculation for variable line heights

bundles/org.eclipse.ui.editors/META-INF/MANIFEST.MF

@@ -2,7 +2,7 @@ Manifest-Version: 1.0
 Bundle-ManifestVersion: 2
 Bundle-Name: %pluginName
 Bundle-SymbolicName: org.eclipse.ui.editors; singleton:=true
-Bundle-Version: 3.21.0.qualifier
+Bundle-Version: 3.21.100.qualifier
 Bundle-Activator: org.eclipse.ui.internal.editors.text.EditorsPlugin
 Bundle-ActivationPolicy: lazy
 Bundle-Vendor: %providerName

bundles/org.eclipse.ui.editors/src/org/eclipse/ui/internal/texteditor/stickyscroll/StickyScrollingControl.java

@@ -331,7 +331,10 @@ private void calculateAndSetStickyLinesCanvasBounds() {
 		StyledText textWidget= sourceViewer.getTextWidget();
 
 		int numberStickyLines= getNumberStickyLines();
-		int lineHeight= stickyLineText.getLineHeight() * numberStickyLines;
+		int lineHeight= 0;
+		for (int i= 0; i < numberStickyLines; i++) {
+			lineHeight+= stickyLineText.getLineHeight(stickyLineText.getOffsetAtLine(i));
+		}
 		int spacingHeight= stickyLineText.getLineSpacing() * (numberStickyLines - 1);
 		int separatorHeight= bottomSeparator.getBounds().height;
 
@@ -450,7 +453,8 @@ private boolean areStickyLinesOutDated(StyledText textWidget) {
 	}
 
 	private void limitVisibleStickyLinesToTextWidgetHeight(StyledText textWidget) {
-		int lineHeight= textWidget.getLineHeight() + textWidget.getLineSpacing();
+		int topOffset= textWidget.getOffsetAtLine(textWidget.getTopIndex());
+		int lineHeight= textWidget.getLineHeight(topOffset) + textWidget.getLineSpacing();
 		int textWidgetHeight= textWidget.getBounds().height;
 
 		int visibleLinesInTextWidget= textWidgetHeight / lineHeight;

tests/org.eclipse.ui.editors.tests/META-INF/MANIFEST.MF

@@ -2,7 +2,7 @@ Manifest-Version: 1.0
 Bundle-ManifestVersion: 2
 Bundle-Name: %Plugin.name
 Bundle-SymbolicName: org.eclipse.ui.editors.tests;singleton:=true
-Bundle-Version: 3.14.0.qualifier
+Bundle-Version: 3.14.100.qualifier
 Bundle-Vendor: %Plugin.providerName
 Bundle-Localization: plugin
 Export-Package: org.eclipse.jface.text.tests.codemining,

tests/org.eclipse.ui.editors.tests/src/org/eclipse/ui/internal/texteditor/stickyscroll/StickyScrollingControlTest.java

@@ -17,6 +17,7 @@
 import static org.hamcrest.Matchers.greaterThan;
 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 static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 
@@ -236,6 +237,31 @@ void testStyling() {
 		assertEquals(hoverColor, stickyLineText.getForeground());
 	}
 
+	@Test
+	void testCanvasBoundsHeightAdjustsForVariableLineHeights() {
+		sourceViewer.getTextWidget().setBounds(0, 0, 200, 200);
+
+		// Step 1: Set 2 plain-text sticky lines and record canvas height
+		List<IStickyLine> plainLines = List.of(
+				new StickyLineStub("line 1", 0),
+				new StickyLineStub("line 2", 1));
+		stickyScrollingControl.setStickyLines(plainLines);
+		Canvas stickyControlCanvas = getStickyControlCanvas(shell);
+		int heightWithPlainText = stickyControlCanvas.getBounds().height;
+
+		// Step 2: Replace second sticky line with emoji requiring more vertical space
+		List<IStickyLine> emojiLines = List.of(
+				new StickyLineStub("line 1", 0),
+				new StickyLineStub("\uD83D\uDE00\uD83D\uDE80\uD83C\uDF1F", 1));
+		stickyScrollingControl.setStickyLines(emojiLines);
+		stickyControlCanvas = getStickyControlCanvas(shell);
+		int heightWithEmoji = stickyControlCanvas.getBounds().height;
+
+		// Step 3: Assert emoji causes taller canvas (documents the actual bug)
+		assertTrue(heightWithEmoji > heightWithPlainText,
+				"Canvas height should increase when sticky lines contain emoji with larger line heights");
+	}
+
 	@Test
 	void testLayoutStickyLinesCanvasOnResize() {
 		sourceViewer.getTextWidget().setBounds(0, 0, 200, 200);