Bug 31720 Browsing views should add listener to page [Browsing]
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/browsing/JavaBrowsingPart.java
if (fHasCustomFilter)
			fCustomFiltersActionGroup= new CustomFiltersActionGroup(this, fViewer);
	}
	
	/**
	 * Returns the shell to use for opening dialogs.
	 * Used in this class, and in the actions.
	 */
	Shell getShell() {
		return fViewer.getControl().getShell();
	}
	protected final Display getDisplay() {
		return fViewer.getControl().getDisplay();
	}	
	/**
	 * Returns the selection provider.
	 */
	ISelectionProvider getSelectionProvider() {
		return fViewer;
	}
	/**
	 * 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
	 */
	abstract protected boolean isValidInput(Object element);
	/**