Bug 81983 [preferences] Disabling and enabling folding on small file takes forever
3.1 M4 Using enable/disable folding on a small CU takes forever. This is caused by the recent change to apply the preference to all Java editors. In another (hidden) window (Debug) I had StyledText open which (understandably) took long to react on the preference change. Non-visible editor's should not react to this change until they become visible.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/JavaEditor.java
*/
				public IInformationControlCreator getInformationPresenterControlCreator() {
					return fControlCreator;
				}
			}
			ISourceViewer sourceViewer= getSourceViewer();
			if (sourceViewer == null) {	
				fTextOperationAction.run();
				return;
			}
				
			if (sourceViewer instanceof ITextViewerExtension4)  {
				ITextViewerExtension4 extension4= (ITextViewerExtension4) sourceViewer;
				if (extension4.moveFocusToWidgetToken())
					return;
			}
			
			if (! (sourceViewer instanceof ITextViewerExtension2)) {
				fTextOperationAction.run();
				return;
			}
				
			ITextViewerExtension2 textViewerExtension2= (ITextViewerExtension2) sourceViewer;
			
			
			ITextHover textHover= textViewerExtension2.getCurrentTextHover();
			if (textHover == null) {
				fTextOperationAction.run();
				return;				
			}