### Eclipse Workspace Patch 1.0
#P org.eclipse.compare
Index: compare/org/eclipse/compare/internal/CompareMessages.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.compare/plugins/org.eclipse.compare/compare/org/eclipse/compare/internal/CompareMessages.java,v
retrieving revision 1.17.4.3
diff -u -r1.17.4.3 CompareMessages.java
--- compare/org/eclipse/compare/internal/CompareMessages.java	21 Jul 2008 15:12:12 -0000	1.17.4.3
+++ compare/org/eclipse/compare/internal/CompareMessages.java	22 Jul 2008 12:20:25 -0000
@@ -118,6 +118,7 @@
 	public static String CompareWithOther_error_empty;
 	public static String CompareWithOther_clear;
 	public static String CompareWithOther_warning_two_way;
+	public static String CompareWithOther_info;
 
 	static {
 		NLS.initializeMessages(BUNDLE_NAME, CompareMessages.class);
Index: compare/org/eclipse/compare/internal/CompareWithOtherResourceDialog.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.compare/plugins/org.eclipse.compare/compare/org/eclipse/compare/internal/Attic/CompareWithOtherResourceDialog.java,v
retrieving revision 1.1.2.3
diff -u -r1.1.2.3 CompareWithOtherResourceDialog.java
--- compare/org/eclipse/compare/internal/CompareWithOtherResourceDialog.java	21 Jul 2008 15:12:12 -0000	1.1.2.3
+++ compare/org/eclipse/compare/internal/CompareWithOtherResourceDialog.java	22 Jul 2008 12:20:25 -0000
@@ -398,6 +398,7 @@
 		super.createButtonsForButtonBar(parent);
 		okButton = getButton(IDialogConstants.OK_ID);
 		updateErrorInfo();
+		setMessage(CompareMessages.CompareWithOther_info);
 	}
 
 	private void setSelection(ISelection selection) {
@@ -451,7 +452,7 @@
 						IMessageProvider.ERROR);
 				okButton.setEnabled(false);
 			} else {
-				setMessage(null);
+				setMessage(CompareMessages.CompareWithOther_info);
 				okButton.setEnabled(true);
 			}
 		}
Index: compare/org/eclipse/compare/internal/CompareWithOtherResourceAction.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.compare/plugins/org.eclipse.compare/compare/org/eclipse/compare/internal/Attic/CompareWithOtherResourceAction.java,v
retrieving revision 1.1.2.2
diff -u -r1.1.2.2 CompareWithOtherResourceAction.java
--- compare/org/eclipse/compare/internal/CompareWithOtherResourceAction.java	16 Jul 2008 10:45:52 -0000	1.1.2.2
+++ compare/org/eclipse/compare/internal/CompareWithOtherResourceAction.java	22 Jul 2008 12:20:25 -0000
@@ -22,7 +22,7 @@
 
 /**
  * The "Compare with other resource" action
- * 
+ *
  * @since 3.4
  */
 public class CompareWithOtherResourceAction implements IObjectActionDelegate {
@@ -48,6 +48,7 @@
 			StructuredSelection ss = new StructuredSelection(resources);
 			CompareAction ca = new CompareAction();
 			ca.setActivePart(null, fWorkbenchPart);
+			ca.doesntNeedSelection();
 			if (ca.isEnabled(ss))
 				ca.run(ss);
 		}
Index: compare/org/eclipse/compare/internal/CompareMessages.properties
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.compare/plugins/org.eclipse.compare/compare/org/eclipse/compare/internal/CompareMessages.properties,v
retrieving revision 1.27.4.3
diff -u -r1.27.4.3 CompareMessages.properties
--- compare/org/eclipse/compare/internal/CompareMessages.properties	21 Jul 2008 15:12:12 -0000	1.27.4.3
+++ compare/org/eclipse/compare/internal/CompareMessages.properties	22 Jul 2008 12:20:25 -0000
@@ -128,5 +128,6 @@
 CompareWithOther_dialogMessage=Select resources to compare
 CompareWithOther_error_not_comparable=Selected resources are not comparable.
 CompareWithOther_error_empty=Both left and right panel must contain a valid path.
-CompareWithOther_warning_two_way=Ancestor is not a valid resource. Two-way compare will be performed. 
-CompareWithOther_clear=Clear
\ No newline at end of file
+CompareWithOther_warning_two_way=Ancestor is not a valid resource. Two-way compare will be performed.
+CompareWithOther_clear=Clear
+CompareWithOther_info=Drag files from Package Explorer or from another field within the dialog.
Index: compare/org/eclipse/compare/internal/CompareAction.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.compare/plugins/org.eclipse.compare/compare/org/eclipse/compare/internal/CompareAction.java,v
retrieving revision 1.20.8.2
diff -u -r1.20.8.2 CompareAction.java
--- compare/org/eclipse/compare/internal/CompareAction.java	16 Jul 2008 10:45:52 -0000	1.20.8.2
+++ compare/org/eclipse/compare/internal/CompareAction.java	22 Jul 2008 12:20:25 -0000
@@ -28,14 +28,19 @@
 
 	private ResourceCompareInput fInput;
 	private IWorkbenchPage fWorkbenchPage;
+	private boolean needsSelectionSetting = true;
 
 
 	public void run(ISelection selection) {
+		boolean ok;
 		if (fInput != null) {
-			// Pass the shell so setSelection can prompt the user for which
-			// resource should be the ancestor
-			boolean ok = fInput.setSelection(selection,
-				fWorkbenchPage.getWorkbenchWindow().getShell());
+			if (needsSelectionSetting)
+				// Pass the shell so setSelection can prompt the user for which
+				// resource should be the ancestor
+				ok = fInput.setSelection(selection,
+						fWorkbenchPage.getWorkbenchWindow().getShell());
+			else
+				ok = fInput.setSelection(selection, null);
 			if (!ok) return;
 			fInput.initializeCompareConfiguration();
 			CompareUI.openCompareEditorOnPage(fInput, fWorkbenchPage);
@@ -61,4 +66,8 @@
 	public void setActivePart(IAction action, IWorkbenchPart targetPart) {
 		fWorkbenchPage= targetPart.getSite().getPage();
 	}
+
+	public void doesntNeedSelection() {
+		needsSelectionSetting = false;
+	}
 }
Index: compare/org/eclipse/compare/internal/ResourceCompareInput.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.compare/plugins/org.eclipse.compare/compare/org/eclipse/compare/internal/ResourceCompareInput.java,v
retrieving revision 1.38.8.2
diff -u -r1.38.8.2 ResourceCompareInput.java
--- compare/org/eclipse/compare/internal/ResourceCompareInput.java	16 Jul 2008 10:45:52 -0000	1.38.8.2
+++ compare/org/eclipse/compare/internal/ResourceCompareInput.java	22 Jul 2008 12:20:25 -0000
@@ -207,16 +207,23 @@
 		fThreeWay= selection.length == 3;
 		
 		if (fThreeWay) {
-			SelectAncestorDialog dialog =
-				new SelectAncestorDialog(shell, selection);
-			int code = dialog.open();
-			if (code == Window.CANCEL)
-				return false;
-			
-			fAncestorResource= dialog.ancestorResource;
-			fAncestor= getStructure(fAncestorResource);
-			fLeftResource= dialog.leftResource;
-			fRightResource= dialog.rightResource;
+			if (shell != null) {
+				SelectAncestorDialog dialog =
+					new SelectAncestorDialog(shell, selection);
+				int code = dialog.open();
+				if (code == Window.CANCEL)
+					return false;
+
+				fAncestorResource= dialog.ancestorResource;
+				fAncestor= getStructure(fAncestorResource);
+				fLeftResource= dialog.leftResource;
+				fRightResource= dialog.rightResource;
+			} else {
+				fAncestorResource = selection[0];
+				fAncestor = getStructure(selection[0]);
+				fLeftResource= selection[1];
+				fRightResource= selection[2];
+			}
 		} else {
 			fAncestorResource= null;
 			fAncestor= null;