Bug 22380 "No Source" class file editor does not fetch keyboard focus
Build N20020813 Test Case: 1. From the package explorer open a class from a JAR without attached source 2. Activate the editor 3. Select something in another view (note: selection is blue) 4. Activate the class file editor by clicking on the tab ==> selection in other view remains blue but should be gray. Suggest to set the keyboard focus to the "Attach Source..." button
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/ClassFileEditor.java
IJavaElement element= file.getParent();
		while (element != null && element.getElementType() != IJavaElement.PACKAGE_FRAGMENT_ROOT)
			element= element.getParent();
		return (IPackageFragmentRoot) element;		
	}
	private JavaModelException probeInputForSource(IEditorInput input) {
		if (input == null)
			return null;
		IClassFileEditorInput classFileEditorInput= (IClassFileEditorInput) input;
		IClassFile file= classFileEditorInput.getClassFile();
			
		try {
			file.getSourceRange();
		} catch (JavaModelException e) {
			return e;			
		}
		return null;
	}
	/**
	 * Checks if the class file input has no source attached. If so, a source attachment form is shown.
	 */
	private void verifyInput(IEditorInput input) throws CoreException {
		if (fParent == null || input == null)
			return;
		IClassFileEditorInput classFileEditorInput= (IClassFileEditorInput) input;
		IClassFile file= classFileEditorInput.getClassFile();
		
		
		if (file.getSourceRange() == null) {