Bug 32656 Open/Close project in package explorer looses selection on java-projects. [package explorer]
Not on non-java projects, which looks wrong when multiple java- and non-java-projects are opened/closed.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/PackageExplorerPart.java
if (element == null) 
			element= input;
				
		if (element != null) {
			ISelection newSelection= new StructuredSelection(element);
			if (!fViewer.getSelection().equals(newSelection)) {
				try {
					fViewer.removeSelectionChangedListener(fSelectionListener);						
					fViewer.setSelection(newSelection);
	
					while (element != null && fViewer.getSelection().isEmpty()) {
						
						element= getParent(element);
						if (element != null) {
							newSelection= new StructuredSelection(element);
							fViewer.setSelection(newSelection);
						}
					}
				} finally {
					fViewer.addSelectionChangedListener(fSelectionListener);
				}
			}
			return true;
		}
		return false;
	}
	
	private boolean isOnClassPath(IFile file) {
		IJavaProject jproject= JavaCore.create(file.getProject());
		try {