>BTW, what i mean is that a checkbox should
>not be use to run a command.
>
>IMO, the command button was design to this task.
>
>:-)

In this case the checkbox is NOT running anything, it is turning the timer on and off which is exactly what a checkbox is for binary conditions like ON/OFF, T/F, Y/N etc..

Of course a command button could be used as well with code like this;

* Button's Refresh
IF Thisform.Timer.Enabled
   This.Caption = "Stop Timer"
ELSE
   This.Caption = "Start Timer"
ENDIF

* Button's click event
Thisform.Timer.Enabled = NOT Thisform.Timer.Enabled
This.Refresh()