FileSelectPopup window on wrong monitor

Question

Hello all,
My application is used for display testing and calibration purposes. On the PC where my application is running, the second DVI output is attached to the display to be tested. The second display is driven by enabeling the "Extend my Windows desktop onto this monitor" option in the Display Properties window.
Problem: at some systems, popup windows, like a FileSelectPopup window appear on the second monitor. Since this display is not always visible to the operator, it looks like the application hangs and has to be terminated the hard way (Ctrl-Alt-Del).
How can I make sure that popup windows ALWAYS appear on the monitor where my application is running?
Thanks,
Wim
GEMIDIS - Innovating Display Technology
HQ Ghent, Belgium

Answer 1

Rich, 
I'm not entirely sure what your current problem is, so I'll explain the current behavior in 2010 and earlier, and then hopefully give you some tips. In 2010 and earlier when you launch a FileSelectPopup the location and current monitor of the dialog is stored in the registry by Windows. Windows handles this positioning for a certain number of recently launched applications. As long as that information is stored in the registry the file/directory popups will appear in the last location and monitor that you dragged them to, regardless of what monitor is actually launching them. This seems to be the problem you're running into. Unfortunately CVI has no control over where this dialog will appear as it's a dialog that Windows owns.
If you've tried the CVI 2012 beta you'd have seen that the behavior has changed. Now what happens is that when File/Directory Popups are launched they will always appear on the monitor of the panel that launched them. If you drag the popup to a new location, Windows will remember that location and continue to display the popup in that location, so long as the dialog is always launched from the same panel and that panel has not moved. If you move the panel which is calling the popup, then the next time the popup is displayed it will appear on the monitor of the panel that launched it. This should fix the issue you are having.
Unfortunately there's no good workaround for this in CVI 2010 or earlier because CVI doesn't technically "own" those dialogs. I looked into whether you could just delete the settings from the registry, but Windows doesn't make that easy.  Those values are stored on my machine under:
[HKEY_USERS\S-1-5-21-4170831575-233351449-3708798867-15220\Software\Microsoft\Windows\CurrentVersion\Explorer\UserAssist\{CEBFF5CD-ACE2-4F4F-9178-9926F41749EA}\Count]
Every individual process name has it's own entry so theoretically, you could search for the name of your executable and delete that key, but it seems that Windows scrambles the names using a ROT13. My guess is that they're doing this so that users don't edit these entries themselves, and bad things might occur if you try.
I'm sorry we don't have a better solution for you currently, but at least the problem has already been fixed going forward.
Kevin B.
National Instruments