Have encountered an interesting problem with ActiveX "Reg Event Callback" in LV7 
(WinXP):

In a nutshell, when a lot of events fire in rapid succession, the user-interface locks 
up. 

The events still fire, and the front panel controls update, but the front panel will 
not respond to clicks. Interestingly, if the block diagram is open, you can stop it 
and turn on execution highlighting, etc...

- I've discovered that the problem we're encountering is related to multiple events 
firing before the (reentrant) callback VI has finished executing from the 1st event.
- by watching the Performance data in task manager, and tracking the # of handles used 
by LabVIEW, I find that when this happens, the # of handles increases, but never 
decreases until you stop the VI
- I would expect several (nearly) instantaneous events to launch multiple copies of 
that callback VI, and I can believe that would increase the # handles, but I would 
expect that LabVIEW would catchup shortly thereafter and the # handles would return to 
its starting count.
 
As an aside, using the old ActiveX event and callback method with the exact same 
version of the activeX control does not have this problem, events just queue up and 
then fire appropriately.

Anyone seen anything like this?
Anyone (NI guys) have any ideas?
Follow up question (NI guys): when will the support for the old ActiveX event stuff 
dry up? 

Thanks in advance,
Ben 

Ben Zimmer
[EMAIL PROTECTED]
Software Developer
Meikle Automation
975 Bleams Road, Unit #5
Kitchener, ON    N2E3Z5
Tel: (519)896-0800 x361
Fax: (519)896-0002



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