Custom tSpeedButton painting - firemonkey

Question

I have two TSpeedButton buttons on a form. When one button is enabled, the other is disabled and vice versa. I want to paint the buttons with custom colors to reflect whether they are enabled or disabled.
I coded a procedure named SetButtonsColors. This procedure sets (one button at a time), the variables ButtonFillColor and ButtonStrokeColor with the custom colors, accordingly with the button state, and immediately commands the repainting of the button.
On ButtonPaint handler I set the Canvas.Fill.Color and Canvas.Stroke.Color with ButtonFillColor and ButtonStrokeColor respectively and do the filling and drawing of the aRect.
For my disappointment, the buttons are always painted with the colors set for the last button. This happens, I presume, because Windows paints the buttons asynchronous, and hence, uses the last settings for Canvas.Fill.Color and Canvas.Stroke.Color.
If this is true, how can I force Windows to paint the button immediately after it's repainting is commanded?
Follows the code for SetButtonsColors and ButtonPaint:
procedure tForm1.SetButtonsColors;
begin
if Button1.Enabled then begin
ButtonFillColor := tAlphaColorRec.White;
ButtonStrokeColor := tAlphaColorRec.Black;
Button1.Repaint;
ButtonFillColor := tAlphaColorRec.Black;
ButtonStrokeColor := tAlphaColorRec.White;
Button1.Repaint;
end;
else begin
ButtonFillColor := tAlphaColorRec.Black;
ButtonStrokeColor := tAlphaColorRec.White;
Button1.Repaint;
ButtonFillColor := tAlphaColorRec.White;
ButtonStrokeColor := tAlphaColorRec.Black;
Button2.Repaint;
end;
end;
procedure tForm1.ButtonPaint (Sender: tObject; Canvas: tCanvas; const aRect: tRectF);
begin
Canvas.BeginScene;
Canvas.Fill .Color := lvButtonFillColor;
Canvas.Stroke.Color := lvButtonStrokeColor;
Canvas.FillRect (aRect, 0, 0, [] , 1, CornerTypeBevel);
Canvas.DrawRect (aRect, 0, 0, AllCorners, 1, CornerTypeBevel);
Canvas.EndScene;
end;
Thanks.