Do not inform listeners about selection on ExpandableNode

Fixes #1027

Author: raghucssit

bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/StructuredViewer.java

@@ -33,6 +33,7 @@
 import org.eclipse.jface.util.OpenStrategy;
 import org.eclipse.jface.util.Policy;
 import org.eclipse.jface.util.SafeRunnable;
+import org.eclipse.jface.viewers.internal.ExpandableNode;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.dnd.DragSource;
 import org.eclipse.swt.dnd.DragSourceListener;
@@ -814,6 +815,11 @@ public void run() {
 	 * @see #addPostSelectionChangedListener(ISelectionChangedListener)
 	 */
 	protected void firePostSelectionChanged(final SelectionChangedEvent event) {
+		// do not inform client listeners on ExpandableNode selection
+		if (event.getSelection() instanceof StructuredSelection sel
+				&& sel.getFirstElement() instanceof ExpandableNode) {
+			return;
+		}
 		for (ISelectionChangedListener l : postSelectionChangedListeners) {
 			SafeRunnable.run(new SafeRunnable() {
 				@Override

bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/Viewer.java

@@ -17,6 +17,7 @@
 import org.eclipse.core.runtime.Assert;
 import org.eclipse.core.runtime.ListenerList;
 import org.eclipse.jface.util.SafeRunnable;
+import org.eclipse.jface.viewers.internal.ExpandableNode;
 import org.eclipse.swt.events.HelpEvent;
 import org.eclipse.swt.events.HelpListener;
 import org.eclipse.swt.widgets.Control;
@@ -144,6 +145,13 @@ protected void fireHelpRequested(HelpEvent event) {
 	 * @see ISelectionChangedListener#selectionChanged
 	 */
 	protected void fireSelectionChanged(final SelectionChangedEvent event) {
+
+		// do not inform client listeners on ExpandableNode selection
+		if (event.getSelection() instanceof StructuredSelection sel
+				&& sel.getFirstElement() instanceof ExpandableNode) {
+			return;
+		}
+
 		for (ISelectionChangedListener l : selectionChangedListeners) {
 			SafeRunnable.run(new SafeRunnable() {
 				@Override