Bug 69240 [reconciling] Editor shows "stale" compilation error
Eclipse has always has a small problem in that occaisionally it would show an error in the editor window (red-squiggly, with a marker) even though the error had been fixed and no longer appeared in the Tasks/Problem view. I usually just type "Space-Backspace" and save the file and it goes away. In 3.0, this is MUCH more frequent. I'm not 100% sure of the cause, but every time I've seen in it recently, file A will have a problem, and then I'll change file B to fix it. I'll pay more attention, and see if I can obtain any more details.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/text/JavaReconciler.java
import org.eclipse.jface.text.reconciler.DirtyRegion;
import org.eclipse.jface.text.reconciler.MonoReconciler;
import org.eclipse.ui.IEditorInput;
import org.eclipse.ui.IFileEditorInput;
import org.eclipse.ui.IPartListener;
import org.eclipse.ui.IWorkbenchPart;
import org.eclipse.ui.IWorkbenchPartSite;
import org.eclipse.ui.IWorkbenchWindow;
import org.eclipse.ui.texteditor.ITextEditor;
import org.eclipse.jdt.core.ElementChangedEvent;
import org.eclipse.jdt.core.IElementChangedListener;
import org.eclipse.jdt.core.JavaCore;
import org.eclipse.jdt.internal.ui.JavaPlugin;
import org.eclipse.jdt.internal.ui.javaeditor.CompilationUnitEditor;
 
/**
 * A reconciler that is also activated on editor activation.
 */
public class JavaReconciler extends MonoReconciler {
	
	/**
	 * Internal part listener for activating the reconciler.
	 */
	private class PartListener implements IPartListener {
		
		/*
		 * @see org.eclipse.ui.IPartListener#partActivated(org.eclipse.ui.IWorkbenchPart)
		 */
		public void partActivated(IWorkbenchPart part) {
			if (part == fTextEditor && hasJavaModelChanged())