Bug 5774 Unpredicatable behaviour on double click in packages view
from EC: If you double click a file in the packages view, it opens the file (technically, compilation unit I believe) -- if not already open. However, if the file is already open, a single click selects it as the active editor tag; a double click expands its structure in the packages view. This is unpredictable behavior ;
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/PackageExplorerPart.java
gotoMenu.add(fForwardAction);
		gotoMenu.add(fUpAction);
		gotoMenu.add(fGotoTypeAction);
		gotoMenu.add(fGotoPackageAction);
	}
	private void makeActions() {
		ISelectionProvider provider= getSelectionProvider();
		fOpenCUAction= new OpenResourceAction(provider);
		fPropertyDialogAction= new PropertyDialogAction(getShell(), provider);
		
		fShowNavigatorAction= new ShowInNavigatorAction(provider);
		fAddBookmarkAction= new AddBookmarkAction(provider);
		
		fStandardGroups= new ContextMenuGroup[] {
			new NewGroup(),
			new BuildGroup(),
			new ReorgGroup(),
			new JavaSearchGroup()
		};
		
		fDeleteAction= new DeleteAction(StructuredSelectionProvider.createFrom(provider));
		fRefreshAction= new RefreshAction(getShell());
		fFilterAction = new FilterSelectionAction(getShell(), this, PackagesMessages.getString("PackageExplorer.filters")); 
		fShowLibrariesAction = new ShowLibrariesAction(this, PackagesMessages.getString("PackageExplorer.referencedLibs")); 
		fShowBinariesAction = new ShowBinariesAction(getShell(), this, PackagesMessages.getString("PackageExplorer.binaryProjects")); 
		fFilterWorkingSetAction = new FilterWorkingSetAction(getShell(), this, "Filter Working Set..."); 
		fRemoveWorkingSetAction = new RemoveWorkingSetFilterAction(getShell(), this, "Remove Working Set Filter"); 
		
		fBackAction= new BackAction(fFrameList);
		fForwardAction= new ForwardAction(fFrameList);