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
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					}
				}
			}
		}
			
		if (marker != null && !marker.equals(fLastMarkerTarget)) {
			try {
				boolean isProblem= marker.isSubtypeOf(IMarker.PROBLEM);
				IWorkbenchPage page= getSite().getPage();
				IViewPart view= page.findView(isProblem ? IPageLayout.ID_PROBLEM_VIEW: IPageLayout.ID_TASK_LIST); 
				if (view != null) {
					Method method= view.getClass().getMethod("setSelection", new Class[] { IStructuredSelection.class, boolean.class}); 
					method.invoke(view, new Object[] {new StructuredSelection(marker), Boolean.TRUE });
				}
			} catch (CoreException x) {
			} catch (NoSuchMethodException x) {
			} catch (IllegalAccessException x) {
			} catch (InvocationTargetException x) {
			}
			
		}			
	}
	
	/**
	 * Finds and marks occurrence annotations.
	 * 
	 * @since 3.0
	 */
	class OccurrencesFinderJob extends Job {