High processor usage in Access 2007 application using timers

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MS-Access

Hi all,

I am working on an Access 2007 application in which I have a form in the background on which a timer event is running constantly (every 100 ms).

When I open the accdb file and view the CPU usage on the taskmonitor, everything is ok (Access idling at 0 percent cpu usage unless the user performs an action). However, when I open the VBA code window, cpu usage jumps to 25% and remains constant. Even after I close the code window, cpu usage remains at 25% until the next time that I close Access.

I have tried commenting out all the code in the timer events without change. In fact, I can reproduce the same behaviour in a completely new Access database with only a single form, with the code:

Option Compare Database
Option Explicit

Private Sub Form_Load()
    TimerInterval = 100
End Sub


Private Sub Form_Timer()
    Debug.Print Now
End Sub

Again, if I open this db and open the form, cpu usage is at 0. However if I open the VBA code window (while the form remains open in the background), cpu usage goes up to around 16-19%. This behaviour gets worse the shorter the timer interval is. But even with a short timer (10 ms), cpu usage is at 0 as long as I have not opened the code window...?

I am running 32 bit Access 2007 on 64 bit Windows 7.

Does anybody have an idea what is causing this behaviour?
Thanks in advance!
Max

Edit to say: If I open the exact same accdb file in Access 2010 on my friend's computer, I cannot reproduce the problem. There cpu usage remains at 0 regardless of whether the code window is open or not.