How can I reduce PageControl flicker in Delphi?

In Delphi 2009 I found that the flicker of a PageControl - which occurs during resizing of the form - can be reduced by setting its DoubleBuffered property to true.

However if I add controls to the PageControl tabsheets, they will flicker regardless of their DoubleBuffered property setting. I have also tried with and without runtime themes enabled.

Setting ParentBackground to False for components on the PageControl helped a lot. However this results in a different color of these panel components, they all have a darker background now. Maybe this can be fixed easily (without losing Theme support).

I also installed VCL Fix Pack which has a fix for QC 56252 (TPageControl flickers a lot with active theming).

This is far from perfect, but you might want to use this:

  protected
    procedure WMExitSize(var Message: TMessage); message WM_EXITSIZEMOVE;
    procedure WMEnterSize(var Message: TMessage); message WM_ENTERSIZEMOVE;

procedure TFormMain.WMEnterSize(var Message: TMessage);
begin
  if Assigned(PageControlView.ActivePage) then
    PageControlView.Align := alNone;
end;

procedure TFormMain.WMExitSize(var Message: TMessage);
begin
  if Assigned(PageControlView.ActivePage) then
    PageControlView.Align := alClient;
end;

It's the best I found this far, and will reduce the windows update of your page control. It might be less pretty, though, but that's a matter of opinions...