unexpected changing mechanical action of boolean

[Tim Overfield]

We have some code that has been running without fault in various versions of LabVIEW from 1997.

This has a large number of boolean pushbuttons that are 'Latched Until Released'.

This worked fine when initially complied to LV7.1

Now we have undertaken some changes to the code (nothing to do with these booleans) and the action of the switches during execution appears now to be 'Latch When Released' even though right clicking on them shows the mechanical action that is set has not changed.

Does anyone know of a bug in LabVIEW that can misread the mechanical action of a boolean under certain circumstances (such as using multiple threads, events, etc) ?

Any suggestions gratefully received.

[altenbach]

Are you still using 7.1?

Could you make a stripped down mini version of your VI that still shows the problem.

What kind of events do you have associated with these buttons (e.g. value change, mouse down, mouse up, etc.)?

[Tim Overfield]

Yes we are still using 7.1 for the moment

Producing a stripped down version is difficult as this is a huuugggeee application and I suspect the complexity has something to do with the problem (I have seen issues in previous releases of LabVIEW where pushing the boundaries can cause unrelated problems in LabVIEW).

To my knowledge there are no events relating to the buttons, we are using events elsewhere in the code - I was just surmising that there might be a side effect somewhere.

The code associated with the buttons has not changed (for years).

Thanks for your suggestions though.

[Tim Overfield]

Solution found for those who might be interested.

Problem caused by an entirely unrelated VI which had an 'Open VI Ref' function within in.  This apparantly runs in the same thread as the user interface and has the effect of halting the main loop when the mouse button is depressed.  This then appears as if a momentary pushbutton changes its mechanical action from 'latch whilst pressed' to 'latch when released'.