[GTK] Don't invalidate style context when setting background color #2702

bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Control.java

@@ -5258,7 +5258,6 @@ void setBackgroundGdkRGBA (long handle, GdkRGBA rgba) {
 
 	long context = GTK.gtk_widget_get_style_context(handle);
 	setBackgroundGdkRGBA(context, handle, rgba);
-	if (!GTK.GTK4) GTK3.gtk_style_context_invalidate(context);
 }
 /**
  * Sets the receiver's background image to the image specified

tests/org.eclipse.swt.tests.gtk/ManualTests/org/eclipse/swt/tests/gtk/snippets/Issue2702_DoubleClickBehavior.java

@@ -0,0 +1,65 @@
+/*******************************************************************************
+ * Copyright (c) 2025 Patrick Ziegler and others.
+ *
+ * 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
+ *
+ * Contributors:
+ *     Patrick Ziegler - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.swt.tests.gtk.snippets;
+
+import org.eclipse.swt.*;
+import org.eclipse.swt.graphics.*;
+import org.eclipse.swt.layout.*;
+import org.eclipse.swt.widgets.*;
+
+/**
+ * This snippet demonstrates a missed selection event when updating the
+ * background color within an SWT.Activate event. To reproduce, alternative
+ * between the table and the tree. On each click, the clicked tree/table item
+ * should be selected.
+ *
+ * @see <a href="https://github.com/eclipse-platform/eclipse.platform.swt/issues/2702">Issue 2702</a>
+ */
+public class Issue2702_DoubleClickBehavior {
+	private static Color ACTIVE = new Color(255, 255, 255);
+	private static Color INACTIVE = new Color(248, 248, 248);
+
+	public static void main(String[] args) {
+		Shell shell = new Shell();
+		shell.setLayout(new GridLayout(2, true));
+		shell.setSize(400, 200);
+
+		Tree tree = new Tree(shell,  SWT.FULL_SELECTION);
+		tree.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
+		TreeItem treeItem1 = new TreeItem(tree, SWT.NONE);
+		treeItem1.setText("Tree Item 1");
+		TreeItem treeItem2 = new TreeItem(tree, SWT.NONE);
+		treeItem2.setText("Tree Item 2");
+		tree.addListener(SWT.Activate, event -> tree.setBackground(ACTIVE));
+		tree.addListener(SWT.Deactivate, event -> tree.setBackground(INACTIVE));
+
+		Table table = new Table(shell, SWT.FULL_SELECTION);
+		table.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
+		TableItem tableItem1 = new TableItem(table, SWT.NONE);
+		tableItem1.setText("Table Item 1");
+		TableItem tableItem2 = new TableItem(table, SWT.NONE);
+		tableItem2.setText("Table Item 2");
+		table.addListener(SWT.Activate, event -> table.setBackground(ACTIVE));
+		table.addListener(SWT.Deactivate, event -> table.setBackground(INACTIVE));
+
+		shell.open();
+
+		Display display = shell.getDisplay();
+		while (!shell.isDisposed()) {
+		 	if (!display.readAndDispatch()) {
+		 		display.sleep();
+	 		}
+		}
+	}
+}