[Support]

Hello!
I can’t repeat it unfortunately, maybe some another condition is required..
Is it possible to make a demo with this error?
Which Delphi version do you use?

[UniSoft]

Windows 7
RAD 10.4 with last 2 updates

By the way, bug with GripPos is not fixed

function TsStatusBar.GripPos: TPoint;
begin
  if FCommonData.SkinManager <> nil then
    with FCommonData.SkinManager, SkinData.CommonSkinData do
      if IsValidImgIndex(GripRightBottom) then begin
        Result := Point(Width - ma[GripRightBottom].Width - BorderWidth, Height - ma[GripRightBottom].Height - BorderWidth);
        Exit;
      end;

  Result := Point(Width - GetSystemMetrics(SM_CXSIZEFRAME), Height - GetSystemMetrics(SM_CYSIZEFRAME));
end;

[UniSoft]

I tried to make demo, but it is crashed only under debugger
First I commented try..except
then compile release version…
if I run it from rad studio in debugger, then it crash…
If I open exe in any debugger (OllyDbg, x64dbg, …) they catch Access Violation…

function TacMainWnd.CallPrevWndProc(const Handle: hwnd; const Msg: longint; const WParam: WPARAM; var LParam: LPARAM): LRESULT;
var
  M: TMessage;
begin
  if Assigned(OldWndProc) then begin
    M.Msg := Msg;
    M.WParam := WParam;
    M.LParam := LParam;
    M.Result := 0;
    OldWndProc(M);
    Result := M.Result;
    LParam := M.LParam;
  end
  else
    if Assigned(OldProc) then
      //try
        Result := CallWindowProc(OldProc, Handle, Msg, WParam, LParam)
      //except
      //  Result := 0;
      //end
    else
      Result := 0;
end;

Alternate link to demo (with compiled exe)
__https__://mega.nz/file/xO5BiQpJ#MRE7uX5rWFFbe1gKJ8snE1Fruj8XJiXfuKUqxXNcP_g

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[UniSoft]

I found problem…
“AnVir Task Manager” adds an icon to the tool bar of open/save dialog and it is the reason why it crash.
But anyway strange, if to disable skinning, then there is no crash.
BTW, message 1046 – probably TB_DELETEBUTTON
shit.. and I had this problem before, just forgot :(.

[UniSoft]

This helps to solve that crash
comment WM_DESTROY
What for need to process both WM_DESTROY and WM_NCDESTROY?
WM_NCDESTROY is the last one, so should be enough.

procedure TacDialogWnd.acWndProc(var Message: TMessage);
var
  PS: TPaintStruct;
  X, Y, i: integer;
  cR, rClient: TRect;
begin
  case Message.Msg of
    {WM_DESTROY,} WM_NCDESTROY: begin
      if SkinData.FCacheBmp <> nil then
        SkinData.FCacheBmp.Assign(nil);
  ...
    end;

[UniSoft]

just some explain, what doing AnVir, now you can see why it cause crash

  case Msg of
  WM_DESTROY, WM_CLOSE: 
    begin
      // here is the problem!!! 
      // this call should be after clean up, not before
      CallWindowProc(PrevWndFunc, ...); // !!!

     // After called Destructor all bottom crap can cause an error
	  
      // this called on init time, then add custom buttons
      //  so btncount cotaint number of buttons in toolbat before add new buttons
      //btncount := SendMessageA(Handle, TB_BUTTONCOUNT, 0, 0); //
	  
      // restore previous WndProc
      SetWindowLong(Handle, GWLP_WNDPROC, PrevWndFunc);
	  
      // delete custom buttons
      SendMessageA(Handle, TB_DELETEBUTTON, btncount + 1, 0);
      SendMessageA(Handle, TB_DELETEBUTTON, btncount    , 0);
    end;
  end;

[Support]

Hello!
I have found a potential reason of the problem there.
Plz, wait a new release and check it (v16.12).
Or, I can send you a patched unit if you have sources of the package.

[UniSoft]

Up to you
If you need I can check it before release…

[UniSoft]

Hello!
I Checked v16.12
still have the same crash… 🙁

I can clearly see in the debugger what exactly is going on…
Look

1. AC sets the new Window Pointer

   InitializeACWnd
      OldProc := Pointer(GetWindowLong(CtrlHandle, GWL_WNDPROC));
      NewWndProcInstance := {$IFDEF DELPHI6UP}Classes.{$ENDIF}MakeObjectInstance(acWndProc);
      SetWindowLong(CtrlHandle, GWL_WNDPROC, LONG_PTR(NewWndProcInstance));

2. Now AnVir do the same (and saves OldProc which is actually already = NewWndProcInstance)
3. Closing Dialog
4. Get message WM_DESTROY (Notice! it doesn’t get WM_CLOSE, at least I don’t see it in WinSpy)
Now the AnVir first pass processing to the old wndProc (what is actually = NewWndProcInstance!)
on process of WM_DESTROY – AC restores original OldProc, after that AC deletes NewWndProcInstance
FreeObjectInstance(ListSW.NewWndProcInstance);

   procedure UninitializeACWnd(...
        if Assigned(ListSW.OldProc) then begin
          SetWindowLong(Handle, GWL_WNDPROC, LONG_PTR(ListSW.OldProc));
          ListSW.OldProc := nil;
          if Assigned(ListSW.NewWndProcInstance) then begin
            {$IFDEF DELPHI6UP}Classes.{$ENDIF}FreeObjectInstance(ListSW.NewWndProcInstance);
            ListSW.NewWndProcInstance := nil;
          end;
        end

5. process returns back to the AnVir, where this shit also thinking that restores old WndProc
SetWindowLong(Handle, GWLP_WNDPROC, PrevWndFunc);
BUT! it is a pointer to already deleted NewWndProcInstance
And follow send the messages

        SendMessageA(Handle, TB_DELETEBUTTON, btncount + 1, 0);
         SendMessageA(Handle, TB_DELETEBUTTON, btncount    , 0);

That is the actually reason!

—
BUG with StatusBar still not fixed as well 🙁
to see it:
1. Launch ASkinDemo.exe
2. Select skin: Standard theme
3. Move cursor over StatusBar
Fixed code is few posts up…

[Support]

Thanks for researching, I will check how to avoid this situation.
And StatusBar in standard non-skinned mode will be fixed in the nearest release.

[Author]

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