{usual stuff at the top of the project source file
var hwnd: Word;
begin
if hPrevInst = 0 then
begin
Application.CreateForm(TForm1, Form1);
Application.Run;
end
else
begin
hwnd := FindWindow('TForm1', nil);
if (not IsWindowVisible(hwnd)) then
begin
ShowWindow(hwnd, sw_ShowNormal);
PostMessage(hwnd, wm_User, 0, 0);
end;
else
SetWindowPos(hwnd, HWND_TOP, 0,0,0,0,
SWP_NOSIZE or SWP_NOMOVE);
end;
end.
====================================================
In the form's PAS file add a message response function for the wm_User
message.
====================================================
{in the form declaration}
public
procedure WMUser(var msg: TMessage); message wm_User;
{in the implementation section}
procedure TForm1.WMUser(var msg: TMessage);
begin
Application.Restore;
end;