Author: Jonas Bilinkevicius

Does anybody know how to capture the minimize button press and act on it before it 
actually minimizes the form?

Answer:

You should intercept WM_SYSCOMMAND messages like this:

1   unit Unit1;
2   
3   interface
4   
5   uses
6     SysUtils, WinTypes, WinProcs, Messages, Classes, Graphics, Controls, Forms, 
7   Dialogs;
8   
9   type
10    TForm1 = class(TForm)
11    public
12      procedure WMSysCommand(var Msg: TWMSysCommand); message WM_SYSCOMMAND;
13    end;
14  
15  var
16    Form1: TForm1;
17  
18  implementation
19  
20  {$R *.DFM}
21  
22  procedure TForm1.WMSysCommand;
23  begin
24    if (Msg.CmdType = SC_MINIMIZE) or (Msg.CmdType = SC_MAXIMIZE) then
25      MessageBeep(0);
26    DefaultHandler(Msg);
27  end;
28  
29  end.