TTaskDialog buttons not consistently drawing correctly if VerificationText is non-blank.

[CharlieHeaps]

Non-blank text in the variable VerificationText (which is used to add a check box to the task dialog) causes the neighboring button to fail to draw correctly (text appears but button no). The problem appears inconsistently in the demo app: TTaskDialogsDemo.dproj (the Checkbox example). Have replicated problem in both Delphi 11.3 and 12.1 under Windows 11 in both (32-bit and 64-bit). Problem apparent with multiple (all?) themes and regardless of DPI settings.

Any help/fixes would be hugely appreciated!

Thanks!

[CharlieHeaps]

Hi - I'm still having issues with this not working properly in Delphi 12.3. Would anyone be able to provide some support? I'm afraid the VCL Styles utils code is beyond my programming expertise to tinker with.

[TextEditorPro]

I ran into the same problem, here's how you can fix this.

Vcl.Styles.UxTheme.pas:

function UxTheme_Button(hTheme: hTheme; hndc: hdc; iPartId, iStateId: Integer;
    const pRect: TRect; Foo: Pointer; Trampoline: TDrawThemeBackground;
    LThemeClass: string; hwnd: hwnd): HRESULT; stdcall;
...
{  Comment out following code:
        SaveIndex := SaveDC(hndc);
        try
          LBtnBmp := TBitmap.Create;
          LCanvas := TCanvas.Create;
          try
            LCanvas.Handle := hndc;
            LBtnBmp.PixelFormat := pf24bit;
            LBtnBmp.Transparent := True;
            LBtnBmp.SetSize(pRect.Width, pRect.Height);
            LDC := LBtnBmp.Canvas.Handle;
            LColor := StyleServices.GetSystemColor(clBtnFace);
            DrawStyleFillRect(LDC, pRect, LColor);

            if hwnd <> 0 then
              DrawStyleParentBackground(hwnd, hndc, pRect);

            DrawStyleElement(LDC, LDetails, pRect);

            LCanvas.Draw(0, 0, LBtnBmp);
          finally
            LCanvas.Free;
            LBtnBmp.Free;
          end;
        finally
          RestoreDC(hndc, SaveIndex);
        end; 
}
        // Replace it with this
        SaveIndex := SaveDC(hndc);
        try
          if hwnd <> 0 then
            DrawStyleParentBackground(hwnd, hndc, pRect);

          LColor := StyleServices.GetSystemColor(clBtnFace);
          DrawStyleFillRect(hndc, pRect, LColor);
          DrawStyleElement(hndc, LDetails, pRect);
        finally
          RestoreDC(hndc, SaveIndex);
        end;