Background color of a TTrackBar

[the_magik_mushroom]

Hello,

Simple question:

I have a form with a TrackBar1.
When I paint my form in red, the surrounding of the TrackBar1 stay to default color, until I click on it or it get the focus, then the surrounding becomes red.

Code: Pascal  [Select][+][-]

1. procedure TForm1.Button1Click(Sender: TObject);
2. begin
3.   form1.Color:= clRed;
4. end;  

Any idea how to fix this?
The only solution I've found is to do a loop with SetFocus on all TTrackBars of my form, and I found it not clean.
Thanks

[ASerge]

When I paint my form in red, the surrounding of the TrackBar1 stay to default color, until I click on it or it get the focus, then the surrounding becomes red.

Confirm on Windows. Lazarus 3.8 (and Delphi 7 also). It's seems OS bug.

Any idea how to fix this?
The only solution I've found is to do a loop with SetFocus on all TTrackBars of my form, and I found it not clean.

It is safer to use ActiveControl:

Code: Pascal  [Select][+][-]

1. procedure TForm1.Button1Click(Sender: TObject);
2. var
3.   LastActive: TWinControl;
4.   C: TControl;
5. begin
6.   LastActive := ActiveControl;
7.   Color := clRed;
8.   for C in GetEnumeratorControls do
9.     if C is TTrackBar then
10.       ActiveControl := TTrackBar(C);
11.   ActiveControl := LastActive;
12. end;

[the_magik_mushroom]

Thank you I did this:

Code: Pascal  [Select][+][-]

1. var
2.   LastActive: TWinControl;
3.   C: TControl;
4. begin
5.   LastActive := ActiveControl;
6.  
7.   for C in GetEnumeratorControls do
8.   begin
9.     if C is TTrackBar then
10.     begin
11.       ActiveControl := TTrackBar(C); // Set focus to each TTrackBar.
12.     end;
13.   end;
14.   ActiveControl := LastActive; // Restore the original active control.
15. end;      

[the_magik_mushroom]

Well my problem is it does not work on my app with the ttrackbars been on different panels and tabs.

Code: Pascal  [Select][+][-]

1. [Break]
2. Project1 raised exception class 'EInvalidOperation' with message:
3. Cannot focus a disabled or invisible window
4.  

[ASerge]

Project1 raised exception class 'EInvalidOperation' with message:
Cannot focus a disabled or invisible window

Code: Pascal  [Select][+][-]

1. procedure TForm1.Button1Click(Sender: TObject);
2.  
3.   procedure TouchTrackBars(AWinControl: TWinControl);
4.   var
5.     C: TControl;
6.   begin
7.     if (AWinControl is TTrackBar) and AWinControl.CanFocus then
8.       ActiveControl := AWinControl;
9.     for C in AWinControl.GetEnumeratorControls do
10.       if C is TWinControl then
11.         TouchTrackBars(TWinControl(C));
12.   end;
13.  
14. var
15.   LastActive: TWinControl;
16. begin
17.   LastActive := ActiveControl;
18.   Panel1.Color := clRed;
19.   Panel2.Color := clRed;
20.   Panel2.Enabled := False;
21.   TouchTrackBars(Self);
22.   ActiveControl := LastActive;
23. end;

[the_magik_mushroom]

That works, thanks ASerge