I have an MS Access 2010 Database which is fairly complex. It was originally a 2003 database. I have created a new & very simple form.
If I open the form in 'Design View' it opens instantly.
If I open the form to view it, it opens instantly.
If, when the form is open in normal 'Form View' mode, I right click on the title bar and select 'Design View' it can take anything up to a couple of minutes to open. The form contains almost no code, is not attached to a table, has one unbound fielld in it.
The form is not modal
The form is not pop-up.
The database has been compacted & repaired.
The database has been rebuilt by creating a new file and importing all the objects.
If I open the database in Access 2003, opening the form and switching between form and design view causes no problems.