Author: Jonas Bilinkevicius

My application (non MDI) has many modal forms which are open most of the time. When 
the user wants to minimize the application and presses the minimize system button, 
he experiences only the top modal form gets minimized while the other forms (at 
least app's main form) are still at their current size. Moreover, the user now is 
confused because clicking on the main form does nothing but giving errors to him. I 
can not change the application's appearance or exchange the modal forms to some 
other solution. Is there a way I can keep my modal design and still enable users to 
minimize the application the way they are used to?

Answer:

Add a handler for WM_SYSCOMMAND to your modal forms. The handler should look like 
this:

1   private {form declaration}
2   
3   procedure WMSyscommand(var msg: TWmSysCommand); message WM_SYSCOMMAND;
4   
5   procedure TForm2.WMSyscommand(var msg: TWmSysCommand);
6   begin
7     case (msg.cmdtype and $FFF0) of
8       SC_MINIMIZE:
9         begin
10          msg.result := 0;
11          EnableWindow(Application.handle, true);
12          Application.Minimize;
13        end;
14    else
15      inherited;
16    end;
17  end;