Delphi XE2 VCL styles, updating caption blocks other controls invalidation

Question

Found a glitch with VCL styles: when you update the form caption, other controls previously redrawn within the same procedure don't get repainted, and you are forced to call Repaint, losing valuable processing time to redraw.

Example: (set project options/vcl style manually)

unit Unit11;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Vcl.ExtCtrls;

type
  TForm11 = class(TForm)
    Button1: TButton;
    Panel1: TPanel;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form11: TForm11;

implementation

{$R *.dfm}

procedure TForm11.Button1Click(Sender: TObject);
begin
  Panel1.Caption := 'test';
  caption := 'glitch';
end;

end.

object Form11: TForm11
  Left = 0
  Top = 0
  Caption = 'Form11'
  ClientHeight = 89
  ClientWidth = 352
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  PixelsPerInch = 96
  TextHeight = 13
  object Button1: TButton
    Left = 8
    Top = 8
    Width = 121
    Height = 57
    Caption = 'Button1'
    TabOrder = 0
    OnClick = Button1Click
  end
  object Panel1: TPanel
    Left = 135
    Top = 8
    Width = 185
    Height = 57
    Caption = 'Panel1'
    TabOrder = 1
  end
end

program Project10;

uses
  Vcl.Forms,
  Unit11 in 'Unit11.pas' {Form11},
  Vcl.Themes,
  Vcl.Styles;

{$R *.res}

begin
  Application.Initialize;
  Application.MainFormOnTaskbar := True;
  TStyleManager.TrySetStyle('Cobalt XEMedia');
  Application.CreateForm(TForm11, Form11);
  Application.Run;
end.

Answer 1

Set the caption calls in the sequence.

• First form.caption, then child.caption.

Once you've called the wrong sequence, then stopped working the correct sequence. That's why I use here, the "set default" button.

This proceed, as long as there is no fix for it, I can live with that.

procedure TForm11.Button1Click(Sender: TObject);
begin // wrong order
  Panel1.Caption := 'test';
  caption := 'glitch';
end;

procedure TForm11.Button2Click(Sender: TObject);
begin // right order
  caption := 'glitch';
  Panel1.Caption := 'test';
end;

procedure TForm11.Button3Click(Sender: TObject);
var
i:integer;
begin // count no refresh
  for  i:= 1 to 300 do begin
  caption := 'glitch '+intToStr(i);
  Panel1.Caption := 'test '+intToStr(i);
  end;
end;

procedure TForm11.Button4Click(Sender: TObject);
var
i:integer;
begin // count with refresh
  for  i:= 1 to 300 do begin
  caption := 'glitch '+intToStr(i);
  Panel1.Caption := 'test '+intToStr(i);
  Panel1.Refresh;
  end;
end;

procedure TForm11.Button5Click(Sender: TObject);
begin // set default
  caption := 'Form11';
  Panel1.Caption := 'Panel1';
  Panel1.Refresh;
end;

end.

If you found another solution. Please tell me.