Form takes time to Recalc and causes #Error

I have a form with a lot of textboxes that have formulas based on other
textboxes on the same form. Some even call user-defined functions. But they
all calculate correctly. However, I noticed that it takes time for the form
to finish "calculating" before I can start entering data. About 5-8 seconds.

One strange behaviour is that if a user tries to move one of the form's
scroll bars while it is in "calculating" mode (in status bar), some textboxes
end up showing #Error. But if we wait until it finishes calculating,
everything is ok. Is there any solution to this?

1) Maybe to disable the form until it finishes calculating.
2) Or maybe keep the form hidden until the calculating is finished?

Is this possible in VBA?

Thanks!