With the checkbox set, the underlying code disables screen updates, so you shouldn't see the reports' icons pop up.
But the screen doesn't refresh, or stops refreshing at some point (e.g. The task eventually completes but the progress bar is useless. For i=1 to imax ' imax is usually 30 or so fraction Done=cdbl(i)/cdbl(imax) Application.
If that handle is nonzero, Windows simply stops updating the contents of that window on screen.
If the handle is 0, Windows reenables screen updates to the locked window.
Because Access has no idea that you've turned them off, Access itself occasionally turns on screen updates.
For example, depending on how you open forms and reports in design mode, completely hiding the properties sheet may be difficult.Because the only window you care about locking in Access is the main Access window itself, the In Access 2.0, finding the window handle (the unique integer that identifies every window) for the main Access window was difficult.