Index: generic/tkText.c
==================================================================
--- generic/tkText.c
+++ generic/tkText.c
@@ -2768,11 +2768,11 @@
 				/* Index describing first location. */
     const TkTextIndex *index2Ptr)
 				/* Index describing second location. */
 {
     TkUndoSubAtom *iAtom, *dAtom;
-    TkUndoAtom *redoElem, *undoElem;
+    int canUndo, canRedo;
 
     /*
      * Create the helpers.
      */
 
@@ -2855,12 +2855,12 @@
 
     Tcl_DecrRefCount(seeInsertObj);
     Tcl_DecrRefCount(index1Obj);
     Tcl_DecrRefCount(index2Obj);
 
-    undoElem = textPtr->sharedTextPtr->undoStack->undoStack;
-    redoElem = textPtr->sharedTextPtr->undoStack->redoStack;
+    canUndo = TkUndoCanUndo(textPtr->sharedTextPtr->undoStack);
+    canRedo = TkUndoCanRedo(textPtr->sharedTextPtr->undoStack);
 
     /*
      * Depending whether the action is to insert or delete, we provide the
      * appropriate second and third arguments to TkUndoPushAction. (The first
      * is the 'actionCommand', and the second the 'revertCommand').
@@ -2870,11 +2870,11 @@
 	TkUndoPushAction(textPtr->sharedTextPtr->undoStack, iAtom, dAtom);
     } else {
 	TkUndoPushAction(textPtr->sharedTextPtr->undoStack, dAtom, iAtom);
     }
 
-    if (undoElem == NULL || redoElem != NULL) {
+    if (!canUndo || canRedo) {
         GenerateUndoStackEvent(textPtr);
     }
 }
 
 /*
@@ -5164,11 +5164,10 @@
     Tcl_Obj *const objv[])	/* Argument objects. */
 {
     int index, setModified, oldModified;
     int canRedo = 0;
     int canUndo = 0;
-    TkUndoAtom *redoElem, *undoElem;
 
     static const char *const editOptionStrings[] = {
 	"canundo", "canredo", "modified", "redo", "reset", "separator",
         "undo", NULL
     };
@@ -5247,30 +5246,30 @@
     case EDIT_REDO:
         if (objc != 3) {
 	    Tcl_WrongNumArgs(interp, 3, objv, NULL);
 	    return TCL_ERROR;
 	}
-	undoElem = textPtr->sharedTextPtr->undoStack->undoStack;
+	canUndo = TkUndoCanUndo(textPtr->sharedTextPtr->undoStack);
         if (TextEditRedo(textPtr)) {
 	    Tcl_SetObjResult(interp, Tcl_NewStringObj("nothing to redo", -1));
 	    Tcl_SetErrorCode(interp, "TK", "TEXT", "NO_REDO", NULL);
 	    return TCL_ERROR;
 	}
-        redoElem = textPtr->sharedTextPtr->undoStack->redoStack;
-        if (undoElem == NULL || redoElem == NULL) {
+        canRedo = TkUndoCanRedo(textPtr->sharedTextPtr->undoStack);
+        if (!canUndo || !canRedo) {
             GenerateUndoStackEvent(textPtr);
         }
 	break;
     case EDIT_RESET:
 	if (objc != 3) {
 	    Tcl_WrongNumArgs(interp, 3, objv, NULL);
 	    return TCL_ERROR;
 	}
-        undoElem = textPtr->sharedTextPtr->undoStack->undoStack;
-        redoElem = textPtr->sharedTextPtr->undoStack->redoStack;
+        canUndo = TkUndoCanUndo(textPtr->sharedTextPtr->undoStack);
+        canRedo = TkUndoCanRedo(textPtr->sharedTextPtr->undoStack);
 	TkUndoClearStacks(textPtr->sharedTextPtr->undoStack);
-        if (undoElem != NULL || redoElem != NULL) {
+        if (canUndo || canRedo) {
             GenerateUndoStackEvent(textPtr);
         }
 	break;
     case EDIT_SEPARATOR:
 	if (objc != 3) {
@@ -5282,18 +5281,18 @@
     case EDIT_UNDO:
         if (objc != 3) {
 	    Tcl_WrongNumArgs(interp, 3, objv, NULL);
 	    return TCL_ERROR;
 	}
-        redoElem = textPtr->sharedTextPtr->undoStack->redoStack;
+        canRedo = TkUndoCanRedo(textPtr->sharedTextPtr->undoStack);
 	if (TextEditUndo(textPtr)) {
 	    Tcl_SetObjResult(interp, Tcl_NewStringObj("nothing to undo", -1));
 	    Tcl_SetErrorCode(interp, "TK", "TEXT", "NO_UNDO", NULL);
 	    return TCL_ERROR;
 	}
-        undoElem = textPtr->sharedTextPtr->undoStack->undoStack;
-        if (redoElem == NULL || undoElem == NULL) {
+        canUndo = TkUndoCanUndo(textPtr->sharedTextPtr->undoStack);
+        if (!canRedo || !canUndo) {
             GenerateUndoStackEvent(textPtr);
         }
 	break;
     }
     return TCL_OK;

Index: generic/tkUndo.c
==================================================================
--- generic/tkUndo.c
+++ generic/tkUndo.c
@@ -493,21 +493,11 @@
 
 int
 TkUndoCanRedo(
     TkUndoRedoStack *stack)	/* An Undo/Redo stack */
 {
-    int canRedo = 0;
-    TkUndoAtom *elem = stack->redoStack;
-
-    while (elem != NULL) {
-        if (elem->type != TK_UNDO_SEPARATOR) {
-            canRedo = 1;
-            break;
-        }
-        elem = elem->next;
-    }
-    return canRedo;
+    return stack->redoStack != NULL;
 }
 
 /*
  *----------------------------------------------------------------------
  *
@@ -526,21 +516,11 @@
 
 int
 TkUndoCanUndo(
     TkUndoRedoStack *stack)	/* An Undo/Redo stack */
 {
-    int canUndo = 0;
-    TkUndoAtom *elem = stack->undoStack;
-
-    while (elem != NULL) {
-        if (elem->type != TK_UNDO_SEPARATOR) {
-            canUndo = 1;
-            break;
-        }
-        elem = elem->next;
-    }
-    return canUndo;
+    return stack->undoStack != NULL;
 }
 
 /*
  *----------------------------------------------------------------------
  *