Hi Ben, How are you calling the ActiveX "Reg Event Callback"? Are you also using the "Unregister for Event" node?
If the ActiveX event registration is placed inside a loop, this may cause LabView to lock up. If you are using the Unregister for Event node in conjunction with the Register Event Callback node, the problem occurs because the Unregister for Event node and Register Event Callback node are not running in the same thread. Register Callback Event always runs in the User Interface (UI) Thread while Unregister for Event runs in the Execution thread. Deadlock occurs in the unregistration process since the Unregister for Event node will place a lock on a mutex in the Execution Thread and the Register Event Callback node is never seeing that this mutex is released in the UI Thread. The temporary fix is simply to avoid firing multiple events successively. The issue is new to Labview 7.0 and it has been documented in our Labview database. As far as support the old ActiveX events, there has been no mentioning of phasing that out. As long as the older ActiveX controls continue to exist on future releases of Labview, then support for those controls will continue to exist. And as always, customer input regarding ActiveX and Labview is always appreciated. Thanks and have a great day! Kileen Cheng Applications Engineer National Instruments
