Sorry, I always forget to mention which version of FM I'm using. It is FM12. I am aware of modal windows, I'm just not sure how to use it properly.
I think I've had similar situations and, assuming your are in a script when taking the user to the questionaire, you could try setting allow user abort to off, pause the script on the questionaire, and then when resuming the script you close the window. This should keep the user locked into the questionaire window (toggle window to close status bar and lock) until they perform whatever action you want before exiting the window. However you'll need to test this very carefully because it can be tricky and I always have an emergency exit. Usually this is just a Cancel button that closes the window, possibly deleting an incomplete record if necessary.
Hope that helps.
Yes indeed! Be sure to add a button to the layout that can get you as the developer out of the modal window without risk of being stuck there, or you may have to perform a Force Quit, which can be risky for the file's health and welfare.
Build the cancel/escape button on the layout or into the scripted window navigation before you start testing the modal window. Many of us learned this the hard way when first trying the new Modal windows.