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
}
	}
	
	/**
	 * Returns the Java element wrapped by this editors input.
	 * 
	 * @return the Java element wrapped by this editors input.
	 * @since 3.0
	 */
	abstract protected IJavaElement getInputJavaElement();
	protected void updateStatusLine() {
		ITextSelection selection= (ITextSelection) getSelectionProvider().getSelection();
		Annotation annotation= getAnnotation(selection.getOffset(), selection.getLength());
		setStatusLineErrorMessage(null);
		setStatusLineMessage(null);
		if (annotation != null) {
			try {
				fIsUpdatingAnnotationViews= true;
				updateAnnotationViews(annotation);
			} finally {
				fIsUpdatingAnnotationViews= false;
			}
			if (annotation instanceof IJavaAnnotation && ((IJavaAnnotation) annotation).isProblem())
				setStatusLineMessage(annotation.getText());
		}
	}
	
	/**
	 * Jumps to the matching bracket.
	 */