Problem setting F.P. control's Description property programmatically

[WNM]

Is there a bug in LV v7.1.1 that prevents a front panel control's Description property from being set programmatically  if the context help window is NOT visible at the time the "Desc" property is written?

I have a VI setup to show or hide the context help window depending on whether or not the cursor is over a particular control.

Other logic in the VI determines what text is shown in the context window.

I can trigger a change in the description text (and see that it is being changed with a probe to the write Desc property for the control), yet when I move the cursor over the control to pop up the context help window, I do not see the changed text I would expect.

If I modify the VI to open the context help window just before writing to the Desc property for the control and then close it afterwards (causing an annoying screen flicker as the context help window quickly opens/closes), then the text does make it into the description for the control.

Is this a know "feature" of the Desc property?

[Kevin_H]

Hi Warren,

Would it possible to post an example program of the problem?

Also, I did find an old dicussion forum post that has an example program that might be helpful for you.

Have a great weekend!

Regards,

Kevin H

[WNM]

Sure Kevin. Checkout the attached v7.1.1 example.

[tbd]

Hi Warren,

      Just to further confuse the issue, note that opening and closing within a few ms AFTER writing text also works!(?)  Attached are two versions of your VI, one demonstrates this strange phenomenon, the other uses a different approach to accomplishe the effect you're after - sans-flicker.

Cheers. 

Message Edited by tbd on 01-19-2008 04:07 AM

[WNM]

TBD,

Thanks for the reply and VIs. The Twilight Zone one was interesting. I cannot believe that this property really is supposed to work this way.

I do like your flicker fix (say that 3 times fast) however. I can easily maintain the text string until it is time to display the context help window and then shove it into the property at the last moment.

Thanks!

Warren

[tbd]

A am pleased if flicker-free logic-fix ducks a finniky "feature".

BTW, the mouse-over help pop-up is a nice effect - thanks for demo-ing it - filing this away for the right situation (lonely VI, candle-light, wine,... )

Cheers!

[WNM]

I just discovered one more oddity about this property. While a hidden context help window does not show an update to the window's Description text, the update is made anyway and the new value is held in in the Description property and is available if it is read back from the property. This allows for an alternate work-around where a shift register otherwise used for holding the Description text is replaced by the Description property itself. See attached VI.

Warren

Message Edited by Warren Massey on 01-20-2008 01:01 PM

[tbd]

Shifted-string having to be wired-through every event-case was definately a liability.

Nice solution/workaround!