I noticed the Access Junkie just posted a few links to KB articles that describe hot fixes for some blocking issues. Here are the highlights (or um, low lights):
When you try to run a Microsoft Access project (.adp) in Access 2007, the project may run slowly. Or, the project may take longer than expected to respond to actions that are performed on the project.
Sub form short-cut menu
In Access 2007, you open a Microsoft Office Access 2003 database that contains a custom shortcut menu for a subform. Then, you right-click the subform. When you do this, the default shortcut menu is displayed instead of the custom shortcut menu.
DAO synchronize a replicated db
When you try to use Data Access Object (DAO) code to synchronize a replicated Access 2007 database, you receive the following error message:
Run-time error '3251':
Operation is not supported for this type of object.