Bug 20195 Can't collapse import container in members view [browsing]
F3 - link Java Browsing to active editor - open Java Browsing perspective - open ClassFileDocumentProvider - expand import container in members view - select first import - try to collapse import container.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/browsing/MembersView.java
* @return	the string used as ID for the Help context
	 */
	protected String getHelpContextId() {
		return IJavaHelpContextIds.MEMBERS_VIEW;
	}
	/**
	 * Creates the the viewer of this part.
	 * 
	 * @param parent	the parent for the viewer
	 */
	protected StructuredViewer createViewer(Composite parent) {
		ProblemTreeViewer viewer= new ProblemTreeViewer(parent, SWT.MULTI);
		fMemberFilterActionGroup= new MemberFilterActionGroup(viewer, JavaUI.ID_MEMBERS_VIEW);
		return viewer;
	}
	protected void fillToolBar(IToolBarManager tbm) {
		tbm.add(new LexicalSortingAction(getViewer(), JavaUI.ID_MEMBERS_VIEW));
		fMemberFilterActionGroup.contributeToToolBar(tbm);
	}
	
	/**
	 * Answers if the given <code>element</code> is a valid
	 * input for this part.
	 * 
	 * @param 	element	the object to test
	 * @return	<true> if the given element is a valid input
	 */
	protected boolean isValidInput(Object element) {
		if (element instanceof IType) {
			IType type= (IType)element;