Bug 52474 UI Blocked when opening Java Perspective during CVS check out
build I20040218 - start eclipse with a new workspace - switch to CVS Repository Exploring perspective - check out a number of projects ( i checkout Platform UI module) - now attempt to switch to the Java Perspective NOTE that at this point the "UI is blocked" dialog is opened. Probably due to the fact that starting the Java Perspective requires the workbench lock? The point here is that this will be a common pattern and it would be nice if we could investigate makeing this scenario work more smoothly.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/PackageExplorerPart.java
* Makes the package explorer part visible in the active perspective. If there
	 * isn't a package explorer part registered <code>null</code> is returned.
	 * Otherwise the opened view part is returned.
	 */
	public static PackageExplorerPart openInActivePerspective() {
		try {
			return (PackageExplorerPart)JavaPlugin.getActivePage().showView(VIEW_ID);
		} catch(PartInitException pe) {
			return null;
		}
	} 
		
	 public void dispose() {
		if (fContextMenu != null && !fContextMenu.isDisposed())
			fContextMenu.dispose();
		getSite().getPage().removePartListener(fPartListener);
		JavaPlugin.getDefault().getPreferenceStore().removePropertyChangeListener(this);
		if (fViewer != null)
			fViewer.removeTreeListener(fExpansionListener);
		
		if (fActionSet != null)	
			fActionSet.dispose();
		if (fFilterUpdater != null)
			ResourcesPlugin.getWorkspace().removeResourceChangeListener(fFilterUpdater);
		super.dispose();	
	}
	/**
	 * Implementation of IWorkbenchPart.createPartControl(Composite)
	 */
	public void createPartControl(Composite parent) {