Tab Key doesn't work for text entry boxes in Captivate 3

I'm building a software simulation training where I'm using text entry boxes.  Some use the Enter key as a shortcut, some use the Tab key.  The ones that use the Enter key work fine, the failure caption works and when enter is pressed, it advances to the next screen.  The ones that use the Tab key don't work at all.  The failure caption doesn't work and the Tab key doesn't advance to the next screen.  I've compared the ones that work and the ones that don't work and I can't see any difference.  I've set the text entry box to pause at the end of the slide so there shouldn't be an issue there.  I've even tried having the 'on success' action to be continue rather than go to next slide and use a click box that would use the Tab key as a shortcut to advance to the next screen -- to no avail!  Is there any way that the Tab key could have been disabled somehow?  I'm totally at a loss, Please help!!

Thanks!