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
import org.eclipse.jface.text.TextSelection;
import org.eclipse.jface.text.TextUtilities;
import org.eclipse.jface.text.information.IInformationProvider;
import org.eclipse.jface.text.information.IInformationProviderExtension2;
import org.eclipse.jface.text.information.InformationPresenter;
import org.eclipse.jface.text.link.LinkedModeModel;
import org.eclipse.jface.text.reconciler.IReconciler;
import org.eclipse.jface.text.source.Annotation;
import org.eclipse.jface.text.source.AnnotationRulerColumn;
import org.eclipse.jface.text.source.CompositeRuler;
import org.eclipse.jface.text.source.IAnnotationModel;
import org.eclipse.jface.text.source.IAnnotationModelExtension;
import org.eclipse.jface.text.source.ICharacterPairMatcher;
import org.eclipse.jface.text.source.IOverviewRuler;
import org.eclipse.jface.text.source.ISourceViewer;
import org.eclipse.jface.text.source.ISourceViewerExtension2;
import org.eclipse.jface.text.source.IVerticalRuler;
import org.eclipse.jface.text.source.LineChangeHover;
import org.eclipse.jface.text.source.SourceViewerConfiguration;
import org.eclipse.jface.text.source.projection.ProjectionSupport;
import org.eclipse.jface.text.source.projection.ProjectionViewer;
import org.eclipse.ui.editors.text.DefaultEncodingSupport;
import org.eclipse.ui.editors.text.EditorsUI;
import org.eclipse.ui.editors.text.IEncodingSupport;
import org.eclipse.ui.IEditorActionBarContributor;
import org.eclipse.ui.IEditorInput;
import org.eclipse.ui.IEditorPart;
import org.eclipse.ui.IPageLayout;
import org.eclipse.ui.IPartService;
import org.eclipse.ui.ISelectionListener;