You can minimize it, and it will be a very small rectangular at the bottom-left-hand side of the Access window. And to maximize it, you just click on the maximize button in that small box. Having said that, it is easy for it to hide underneath open forms. When I accidentally minimize them, it took me forever to find out that it was still open but minimized, so just be careful. If you know VBA, you can control all of this by code.

That's exactly what I mean, how do we address that with VBA, minimize it and enlarge it again

Application Window Maximize Restore

With Application Window Maximize Restore you can also call the form with name or is it only the active form.
When opening a new form, I would like to minimize the main form, which is what this code does, but if another form is active, I would like to maximize the previous one when closing it and then I think I should call it with name. Is this possible?

Hi Ludwig,

I can't help but think that what you're trying to do defeats the purpose of having overlapping windows. Why don't you go to tab windows instead?

This will minimize the customer form
    Forms!CustomerF.SetFocus
    DoCmd.Minimize
    
This will restore the customer form
    Forms!CustomerF.SetFocus
    DoCmd.Restore

Note: the target form must be open otherwise an error will be generated.

toppy, that's it. It all seems so simple when you read it. Thank you all :)

can you also make it invisible, now it will be in the bottom left corner, one should not see anything on the screen.

That would be closing it. Im with Sami that seems to defeat purpose of overlapping forms. If you went to tabbed forms you could imitate  the behavior you're wanting. Another question though is Why dont you just close it?  Then when your done on your form, and close it, reopen the main form. There are other ways to get values if your concern is storing settings on your main menu, like tempvars or temporary invisible text boxes