[AccessD] Form flashes on timer event

Dear List:
 
I've got a fairly complex bound form (no sub forms, though) with a timer on
it to keep track of elapsed time (timesheet form for a law firm).  SO they
can start and pause and cancel the timer with a couple of button.  And it
shows the elapsed time.
 
The timer interval is set to 1000 and each time the timer event fires the
screen flashes like it's being repainted.
 
Here's the code snip:
 
Private Sub Form_Timer()
 
If boolTrapErrors = True Then On Error GoTo Err_Form_Timer
 
    mdblTotalHours = mdblTotalHours + ((Me.TimerInterval / 1000) / 60) / 60
    Me.txtElapsedHours = DecHoursToHMS(mdblTotalHours)

where Me.txtElapsedHours  is obviously the box where the elapsed tiem is
being displayed.  
 
This is legacy code.  DecHoursToHMS is a function:
 
    DecHoursToHMS = Format(dblHours / 24, "HH:MM:SS")

Is there a way to stop the flashing?  A2K3 BTW.
 
MTIA
 
Rocky