show diff in "replace with local history" dialog on selection change

team/bundles/org.eclipse.team.ui/src/org/eclipse/team/internal/ui/history/ReplaceLocalHistory.java

@@ -15,17 +15,27 @@
 
 import org.eclipse.compare.CompareConfiguration;
 import org.eclipse.compare.CompareUI;
+import org.eclipse.compare.CompareViewerPane;
 import org.eclipse.compare.structuremergeviewer.ICompareInput;
 import org.eclipse.core.resources.IFile;
 import org.eclipse.core.resources.IFileState;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.jface.action.IAction;
+import org.eclipse.jface.action.IToolBarManager;
+import org.eclipse.swt.SWT;
+import org.eclipse.swt.events.SelectionAdapter;
+import org.eclipse.swt.events.SelectionEvent;
+import org.eclipse.swt.widgets.Composite;
+import org.eclipse.swt.widgets.Control;
+import org.eclipse.swt.widgets.Event;
 import org.eclipse.swt.widgets.Shell;
+import org.eclipse.swt.widgets.Tree;
 import org.eclipse.team.internal.ui.TeamUIMessages;
 import org.eclipse.team.internal.ui.TeamUIPlugin;
 import org.eclipse.team.internal.ui.Utils;
 import org.eclipse.team.ui.history.HistoryPageCompareEditorInput;
 import org.eclipse.team.ui.history.IHistoryPageSource;
+import org.eclipse.ui.part.IPage;
 
 public class ReplaceLocalHistory extends ShowLocalHistory {
 
@@ -54,6 +64,48 @@ public boolean isEditionSelectionDialog() {
 				public String getOKButtonLabel() {
 					return TeamUIMessages.ReplaceLocalHistory_0;
 				}
+
+				@Override
+				protected IPage createPage(CompareViewerPane parent, IToolBarManager toolBarManager) {
+					var page = super.createPage(parent, toolBarManager);
+					Tree tree = getTree(page);
+					runDefaultSelectionEventOnSelectionChange(tree);
+					return page;
+				}
+
+				private void runDefaultSelectionEventOnSelectionChange(Tree tree) {
+					if (tree == null) {
+						return;
+					}
+					tree.addSelectionListener(new SelectionAdapter() {
+
+						@Override
+						public void widgetSelected(SelectionEvent e) {
+							if (tree.getSelectionCount() != 1) {
+								return;
+							}
+							Event event = new Event();
+							event.item = e.item;
+							tree.notifyListeners(SWT.DefaultSelection, event);
+						}
+					});
+				}
+				private Tree getTree(IPage page) {
+					Control control = page.getControl();
+					if (!(control instanceof Composite composite)) {
+						return null;
+					}
+					Control[] children = composite.getChildren();
+					if (children == null) {
+						return null;
+					}
+					for (Control child : children) {
+						if (child instanceof Tree t) {
+							return t;
+						}
+					}
+					return null;
+				}
 				@Override
 				public boolean okPressed() {
 					try {