--- a/dwtx/jface/text/DefaultUndoManager.d	Sun Aug 24 02:22:48 2008 +0200
+++ b/dwtx/jface/text/DefaultUndoManager.d	Sun Aug 24 02:26:23 2008 +0200
@@ -288,7 +288,7 @@
         protected void undoTextChange() {
             try {
                 IDocument document= fTextViewer.getDocument();
-                if (document instanceof IDocumentExtension4)
+                if ( cast(IDocumentExtension4)document )
                     (cast(IDocumentExtension4)document).replace(fStart, fText.length(), fPreservedText, fUndoModificationStamp);
                 else
                     document.replace(fStart, fText.length(), fPreservedText);
@@ -304,7 +304,7 @@
             
             if (isConnected() && isValid()) {
                 IDocument doc= fTextViewer.getDocument();
-                if (doc instanceof IDocumentExtension4) {
+                if ( cast(IDocumentExtension4)doc ) {
                     long docStamp= (cast(IDocumentExtension4)doc).getModificationStamp();
                     
                     // Normal case: an undo is valid if its redo will restore document
@@ -360,7 +360,7 @@
         public bool canRedo() {
             if (isConnected() && isValid()) {
                 IDocument doc= fTextViewer.getDocument();
-                if (doc instanceof IDocumentExtension4) {
+                if ( cast(IDocumentExtension4)doc ) {
                     long docStamp= (cast(IDocumentExtension4)doc).getModificationStamp();
                     return docStamp is IDocumentExtension4.UNKNOWN_MODIFICATION_STAMP || 
                         docStamp is getUndoModificationStamp();
@@ -419,7 +419,7 @@
         protected void redoTextChange() {
             try {
                 IDocument document= fTextViewer.getDocument();
-                if (document instanceof IDocumentExtension4)
+                if ( cast(IDocumentExtension4)document )
                     (cast(IDocumentExtension4)document).replace(fStart, fEnd - fStart, fText, fRedoModificationStamp);
                 else
                     fTextViewer.getDocument().replace(fStart, fEnd - fStart, fText);
@@ -887,7 +887,7 @@
                             // if we are undoing/redoing a command we generated, then ignore
                             // the document changes associated with this undo or redo.
                             if (event.getOperation() instanceof TextCommand) {
-                                if (fTextViewer instanceof TextViewer)
+                                if ( cast(TextViewer)fTextViewer )
                                     (cast(TextViewer)fTextViewer).ignoreAutoEditStrategies(true);
                                 listenToTextChanges(false);
     
@@ -917,7 +917,7 @@
                         public void run() {
                             listenToTextChanges(true);
                             fOperation= null;
-                            if (fTextViewer instanceof TextViewer)
+                            if ( cast(TextViewer)fTextViewer )
                                 (cast(TextViewer)fTextViewer).ignoreAutoEditStrategies(false);
                          }
                     });
@@ -1458,7 +1458,7 @@
      * @since 3.0
      */
     protected void selectAndReveal(int offset, int length) {
-        if (fTextViewer instanceof ITextViewerExtension5) {
+        if ( cast(ITextViewerExtension5)fTextViewer ) {
             ITextViewerExtension5 extension= cast(ITextViewerExtension5) fTextViewer;
             extension.exposeModelRange(new Region(offset, length));
         } else if (!fTextViewer.overlapsWithVisibleRegion(offset, length))