David,
>AddObject() the timer to the _screen, then it can simply:
>
>

_screen.RemoveObject( this.name )

>
>when it's work is done.

Something just occured to me.

Would this be considered anti-OOP because the timer is ASSUMING that it is added to the _Screen? (ie: it is NOT completely encapsulated)

I realize that I could do something like:

_Screen.AddObject('myTimer','myTimer_Class','myWindow',_Screen)

myTimer.Init(cWindowToCheck,oContainer)
if vartype(oContainer)<>'O'
  return .f.
endif
this.oContainer=oContainer

myTimer.TimerEvent()
...
this.oContainer.RemoveObject(this.name)

but it seems like overkill.