Remove flickering from TSpeedButton

Question

Steps to reproduce:

1. Add TPanel to a new VCL form and set Align = alClient .
2. Add TSpeedButton to the panel and assign some bmp image to the Glyph property. (Optional but makes it clearer: Flat = True )
3. Run the application, grab the bottom right corner of the form and move it around. The image in the TSpeedButton will flicker.

I read a lot about getting rid of flickering, but neither of the suggestions seem to work for a TSpeedButton :

• There's no DoubleBuffered property
• WS_EX_COMPOSITED can't be set, because it's not a TWinControl but a TGraphicControl
• WM_ERASEBKGND message isn't received

In case it is of any importance, I'm actually using TPngSpeedButton , but since the actual problem lies within the TSpeedButton , I'm using that in the example.

Is there any solution for this?

Edit: For some reason nobody is able to reproduce this so far, so to make sure it's not my description, here's the dfm:

object Form1: TForm1
  Left = 0
  Top = 0
  Caption = 'Form1'
  ClientHeight = 337
  ClientWidth = 635
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  PixelsPerInch = 96
  TextHeight = 13
  object Panel1: TPanel
    Left = 0
    Top = 0
    Width = 635
    Height = 337
    Align = alClient
    Caption = 'Panel1'
    TabOrder = 0
    object SpeedButton1: TSpeedButton
      Left = 64
      Top = 56
      Width = 32
      Height = 32
      Flat = True
      Glyph.Data = {
        360C0000424D360C000000000000360000002800000020000000200000000100
        180000000000000C000000000000000000000000000000000000FFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CED241C
        ED241CED241CED241CED241CED241CED241CED241CED241CED241CED241CED24
        1CED241CED241CED241CED241CED241CED241CED241CED241CEDFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CED241C
        ED241CED241CED241CED241CED241CED241CED241CED241CED241CED241CED24
        1CED241CED241CED241CED241CED241CED241CED241CED241CEDFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CED241C
        ED241CED241CED241CED241CED241CED241CED241CED241CED241CED241CED24
        1CED241CED241CED241CED241CED241CED241CED241CED241CEDFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CED241C
        ED241CED241CED241CED241CED241CED241CED241CED241CED241CED241CED24
        1CED241CED241CED241CED241CED241CED241CED241CED241CEDFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CED241C
        ED241CED241CED241CED241CED241CED241CED241CED241CED241CED241CED24
        1CED241CED241CED241CED241CED241CED241CED241CED241CEDFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDCC483FCC483F
        CC483FCC483FCC483FCC483FCC483F241CED241CED241CED241CED241CEDCC48
        3FCC483FCC483FCC483FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDCC483FCC483F
        CC483FCC483FCC483FCC483FCC483F241CED241CED241CED241CED241CEDCC48
        3FCC483FCC483FCC483FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDCC483FCC483F
        CC483FCC483FCC483FCC483FCC483F241CED241CED241CED241CED241CEDCC48
        3FCC483FCC483FCC483FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDCC483FCC483F
        CC483FCC483FCC483FCC483FCC483F241CED241CED241CED241CED241CEDCC48
        3FCC483FCC483FCC483FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDCC483FCC483F
        CC483FCC483FCC483FCC483FCC483F241CED241CED241CED241CED241CED241C
        ED241CED241CED241CED241CED241CED241CED241CED241CED241CED241CED24
        1CED241CED241CED241CED241CED241CED241CED241CED241CEDCC483FCC483F
        CC483FCC483FFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CED241C
        ED241CED241CED241CED241CED241CED241CED241CED241CED241CED241CED24
        1CED241CED241CED241CED241CED241CED241CED241CED241CEDCC483FCC483F
        CC483FCC483FFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CED241C
        ED241CED241CED241CED241CED241CED241CED241CED241CED241CED241CED24
        1CED241CED241CED241CED241CED241CED241CED241CED241CEDCC483FCC483F
        CC483FCC483FFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CED241C
        ED241CED241CED241CED241CED241CED241CED241CED241CED241CED241CED24
        1CED241CED241CED241CED241CED241CED241CED241CED241CEDCC483FCC483F
        CC483FCC483FFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CED241C
        ED241CED241CED241CED241CED241CED241CED241CED241CED241CED241CED24
        1CED241CED241CED241CED241CED241CED241CED241CED241CEDCC483FCC483F
        CC483FCC483FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFCC483FCC48
        3FCC483FCC483FCC483FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFCC483FCC483F
        CC483FCC483FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFCC483FCC48
        3FCC483FCC483FCC483FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFCC483FCC483F
        CC483FCC483FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFCC483FCC48
        3FCC483FCC483FCC483FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFCC483FCC483F
        CC483FCC483FCC483FCC483FCC483FCC483FCC483FCC483FCC483FCC483FCC48
        3FCC483FCC483FCC483FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFCC483FCC483F
        CC483FCC483FCC483FCC483FCC483FCC483FCC483FCC483FCC483FCC483FCC48
        3FCC483FCC483FCC483FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFCC483FCC483F
        CC483FCC483FCC483FCC483FCC483FCC483FCC483FCC483FCC483FCC483FCC48
        3FCC483FCC483FCC483FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFCC483FCC483F
        CC483FCC483FCC483FCC483FCC483FCC483FCC483FCC483FCC483FCC483FCC48
        3FCC483FCC483FCC483FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF}
    end
  end
end

And this is how it looks . In reality it's a little bit faster, but the captured video and gif conversion slows it down a bit.

Answer 1

I was actually able to reproduce it on Windows 7 with Delphi 10.2.3 Tokyo. I have had similar problems quite often and since then I've been using this settings for all TPanel and its descendants, which worked in this case as well.

Panel1.DoubleBuffered := True;
Panel1.ParentBackground := False;