I do it all the time. What you'll
probably want to do is just hide the form  so it stays loaded, but gets out
of the way. You can unload it later, before you bail the app...although it
SHOULD be unloaded when the app closes. But I prefer to unload stuff with
code just to make sure.

Also, if you're activating a sub from an OK click in a form, although it's
not always necessary, I generally enter the mod name first...mostly because
it helps me more easily remember the sub's name.

In other words, say the user  clicks OK and info from a dialog box  is going
to go into a doc. I might hide the form, and call the sub to process  the
info, like...

modMain.FillDoc

Not so much because it needs the extra kick to find the sub, but because I
might forget the exact name, so I'll get a list once I hit the period after
modMain.

Once the info is inserted in the doc, I unload the form before the sub ends.

This is handy for having a code  library mod that you can easily move into a
project and then call your standard subs for processing.