Bug 30291 SearchUsagesInFileAction should show dialog in case of failures
Build I20030122 SearchUsagesInFileAction should show a dialog in failure/error cases (e.g. code resolve fails).
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/search/SearchUsagesInFileAction.java
public SearchUsagesInFileAction(JavaEditor editor) {
		super(SearchMessages.getString("Search.FindUsageInFile.label")); 
		setToolTipText(SearchMessages.getString("Search.FindUsageInFile.tooltip")); 
		
		fEditor= editor;
		boolean enabled= false;
		if (getClassFile() != null || SelectionConverter.getInputAsCompilationUnit(fEditor) != null)
			enabled= true;
		setEnabled(enabled); 
	}
		
	/* (non-JavaDoc)
	 * Method declared in IAction.
	 */
	public final  void run() {
		ITextSelection ts= getTextSelection();
		final CompilationUnit root= createAST();
		if (root == null)
			return;
		ASTNode node= NodeFinder.perform(root, ts.getOffset(), ts.getLength());
		
		if (!(node instanceof Name))
			return;
 
		final Name name= (Name)node;
		final IBinding target= name.resolveBinding();
		
		if (target == null)
			return;