Bug 52857 [spell checking] spell checking does not work for reused editors
3.0 M7 0. enable spell checking 1. set the editor preference to close editors automatically (allow only 1 editor) 2. open a CU with misspelled words in the Java editor ==> observe: spell check warnings appear 3. open another CU with misspelled words in the Java editor ==> observe: no spell check warnings
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/text/spelling/SpellReconcileStrategy.java
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.jface.preference.IPreferenceStore;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.IRegion;
import org.eclipse.jface.text.ITypedRegion;
import org.eclipse.jface.text.TextUtilities;
import org.eclipse.jface.text.reconciler.DirtyRegion;
import org.eclipse.jface.text.reconciler.IReconcilingStrategy;
import org.eclipse.jface.text.reconciler.IReconcilingStrategyExtension;
import org.eclipse.jface.text.source.IAnnotationModel;
import org.eclipse.ui.texteditor.ITextEditor;
import org.eclipse.jdt.core.IProblemRequestor;
import org.eclipse.jdt.core.compiler.IProblem;
import org.eclipse.jdt.internal.ui.JavaUIMessages;
import org.eclipse.jdt.internal.ui.text.spelling.engine.ISpellCheckEngine;
import org.eclipse.jdt.internal.ui.text.spelling.engine.ISpellCheckPreferenceKeys;
import org.eclipse.jdt.internal.ui.text.spelling.engine.ISpellChecker;
import org.eclipse.jdt.internal.ui.text.spelling.engine.ISpellEvent;
import org.eclipse.jdt.internal.ui.text.spelling.engine.ISpellEventListener;
/**
 * Reconcile strategy to spell-check comments.
 * 
 * @since 3.0
 */
public class SpellReconcileStrategy implements IReconcilingStrategy, IReconcilingStrategyExtension, ISpellEventListener {
	/**
	 * Spelling problem to be accepted by problem requestors.
	 */
	public class SpellProblem implements IProblem {