Form suddenly disappears

I have an Access 2010 database with a form containing a tab-control. I've slowly been adding several stand-alone forms as pages on the tab-control. I just added 2 more, and all of a sudden the form does not display in Form mode. It doesn't even get to the Activate event.

I removed the last two pages - the ones that I had just added, but the form is still non-operable.

I've never seen this before and am stumped as to how to proceed. I'm getting ready to dump some basic data (numer & types of controls, etc) but in the meantime has anyone ever seen this before?

Thanks,

Tony

Some additional information.

I can track the form's activity through the Load event, but then it never makes it to the Activate event. (This matches, as far as I can tell) the visual symptoms, where the form is seen to be available, but there is nothing there.

I'm nowhere close to the limit on the number of controls:
Summary report for form CCCBR (CCCBR Master form)
CCCBR (CCCBR Master form) has 49 Text boxes
CCCBR (CCCBR Master form) has 16 Check boxes
CCCBR (CCCBR Master form) has 3 Combo boxes
CCCBR (CCCBR Master form) has 16 Check boxes
CCCBR (CCCBR Master form) has 13 Command Buttons
CCCBR (CCCBR Master form) has 90 Labels
CCCBR (CCCBR Master form) has 1 List boxes
CCCBR (CCCBR Master form) has 9 Pages
CCCBR (CCCBR Master form) has 0 Radio buttons
CCCBR (CCCBR Master form) has 1 Tab controls
CCCBR (CCCBR Master form) has 0 Toggle buttons

The form consistently uses about 288/292 KB of memory when it is 'loaded', and releases most of it when it is closed. So, something is going on!

Tony

Do you think you can share this file without any PII or confidential data?

Thanks for the response. Another source discovered that I had somehow, inadvertently set the Visible attribute of the detail area to false. Access was simply doing what it thought I wanted! Now of course I have to re-program myself to avoid such egregious fat-fingering!

Tony