Bug 31081 Double clicking in packages viewer expands/collapses tree node
Build I20030205 - preference double click open mode - show member of compilation unit - double click on a CU observe: tree node gets expanded
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/PackageExplorerActionGroup.java
void fillViewMenu(IMenuManager menu) {
		if (showCompilationUnitChildren()) {
			fMemberFilterActionGroup.contributeToViewMenu(menu);
		}
		menu.add(new Separator(IWorkbenchActionConstants.MB_ADDITIONS));
		menu.add(new Separator(IWorkbenchActionConstants.MB_ADDITIONS+"-end"));		
	}
	 void handleSelectionChanged(SelectionChangedEvent event) {
		fZoomInAction.update();
	}
	
	public void fillContextMenu(IMenuManager menu) {		
		IStructuredSelection selection= (IStructuredSelection)getContext().getSelection();
		int size= selection.size();
		Object element= selection.getFirstElement();
		
		addGotoMenu(menu, element, size);
		
		addOpenNewWindowAction(menu, element);
		
		super.fillContextMenu(menu);
	}
	
	 private void addGotoMenu(IMenuManager menu, Object element, int size) {
		
		if (size == 1 && fPart.getViewer().isExpandable(element) && (isGoIntoTarget(element) || element instanceof IContainer))
			menu.appendToGroup(IContextMenuConstants.GROUP_GOTO, fZoomInAction);
	}
	
	private boolean isGoIntoTarget(Object element) {