diff --git a/debugger/debugger.pp b/debugger/debugger.pp
index e8286a6159..4d96c5436d 100644
--- a/debugger/debugger.pp
+++ b/debugger/debugger.pp
@@ -3779,7 +3779,7 @@ end;
 
 procedure TIDEWatches.Update(Item: TCollectionItem);
 var
-  n, m: Integer;
+  n, m, c: Integer;
   Notification: TIDEWatchesNotification;
 begin
   // Note: Item will be nil in case all items need to be updated
@@ -3790,8 +3790,16 @@ begin
 
     if Item = nil
     then begin
-      for m := 0 to Count - 1 do
+      m := 0;
+      c := Count;
+      while m < c do begin;
         Notification.FOnUpdate(Self, Items[m]);
+        if c <> Count then begin
+          m := Max(0, m - Max(0, Count - c));
+          c := Count;
+        end;
+        inc(m);
+      end;
     end
     else begin
       Notification.FOnUpdate(Self, TIDEWatch(Item));
diff --git a/debugger/watchesdlg.pp b/debugger/watchesdlg.pp
index 2b13ad716e..d132cd509b 100644
--- a/debugger/watchesdlg.pp
+++ b/debugger/watchesdlg.pp
@@ -38,12 +38,14 @@ unit WatchesDlg;
 interface
 
 uses
-  Classes, SysUtils, LCLProc, Forms, Controls, Graphics, Dialogs,
+  Classes, SysUtils, LCLProc, Forms, Controls, Graphics, Dialogs, math,
   StdCtrls, Buttons, Menus, ComCtrls, LCLType, ActnList, IDEImagesIntf,
   LazarusIDEStrConsts, Debugger, DebuggerDlg, BaseDebugManager;
 
 type
 
+  TWatchesDlgStateFlags = set of (wdsfUpdating, wdsfNeedDeleteAll, wdsfNeedDeleteCurrent);
+
   { TWatchesDlg }
 
   TWatchesDlg = class(TDebuggerDlg)
@@ -105,6 +107,7 @@ type
     FWatchesNotification: TIDEWatchesNotification;
     FPowerImgIdx, FPowerImgIdxGrey: Integer;
     FUpdateAllNeeded: Boolean;
+    FStateFlags: TWatchesDlgStateFlags;
     function GetSelected: TIDEWatch;
     procedure SetWatches(const AValue: TIDEWatches);
     procedure WatchAdd(const ASender: TIDEWatches; const AWatch: TIDEWatch);
@@ -138,6 +141,7 @@ begin
   FWatchesNotification.OnAdd := @WatchAdd;
   FWatchesNotification.OnUpdate := @WatchUpdate;
   FWatchesNotification.OnRemove := @WatchRemove;
+  FStateFlags := [];
 
   ActionList1.Images := IDEImages.Images_16;
   ToolBar1.Images := IDEImages.Images_16;
@@ -211,8 +215,6 @@ begin
 end;
 
 procedure TWatchesDlg.SetWatches(const AValue: TIDEWatches);
-var
-  i: Integer;
 begin
   if FWatches = AValue then Exit;
 
@@ -230,9 +232,7 @@ begin
     if FWatches <> nil
     then begin
       FWatches.AddNotification(FWatchesNotification);
-
-      for i:=0 to FWatches.Count-1 do
-        WatchUpdate(FWatches, FWatches.Items[i]);
+      UpdateAll;
     end;
     
   finally
@@ -393,7 +393,10 @@ end;
 procedure TWatchesDlg.popDeleteAllClick(Sender: TObject);
 var
   n: Integer;
-begin                                    
+begin
+  Include(FStateFlags, wdsfNeedDeleteAll);
+  if wdsfUpdating in FStateFlags then exit;
+  Exclude(FStateFlags, wdsfNeedDeleteAll);
   try
     DisableAllActions;
     for n := lvWatches.Items.Count - 1 downto 0 do
@@ -416,6 +419,9 @@ procedure TWatchesDlg.popDeleteClick(Sender: TObject);
 var
   Item: TIDEWatch;
 begin
+  Include(FStateFlags, wdsfNeedDeleteCurrent);
+  if (wdsfUpdating in FStateFlags) then exit;
+  Exclude(FStateFlags, wdsfNeedDeleteCurrent);
   try
     DisableAllActions;
     repeat
@@ -523,17 +529,32 @@ procedure TWatchesDlg.UpdateItem(const AItem: TListItem; const AWatch: TIDEWatch
 begin
 // Expression
 // Result
-  AItem.Caption := AWatch.Expression;
   if (not ToolButtonPower.Down) or (not Visible) then exit;
+
+  include(FStateFlags, wdsfUpdating);
+  AItem.Caption := AWatch.Expression;
   AItem.SubItems[0] := ClearMultiline(AWatch.Value);
+  exclude(FStateFlags, wdsfUpdating);
+  if wdsfNeedDeleteCurrent in FStateFlags then
+    popDeleteClick(nil);
+  if wdsfNeedDeleteAll in FStateFlags then
+    popDeleteAllClick(nil);
 end;
 
 procedure TWatchesDlg.UpdateAll;
 var
-  i: Integer;
+  i, l: Integer;
 begin
-  for i:=0 to FWatches.Count-1 do
+  l := FWatches.Count;
+  i := 0;
+  while i < l do begin
     WatchUpdate(FWatches, FWatches.Items[i]);
+    if l <> FWatches.Count then begin
+      i := Max(0, i - Max(0, FWatches.Count - l));
+      l := FWatches.Count;
+    end;
+    inc(i);
+  end;
 end;
 
 procedure TWatchesDlg.DisableAllActions;