Why Does My Program Hang when I use any dropdown Connecteed to a DataSource?

Hello Experts.

I need some help determining why my Visual Studio 2012 VB.NET Windows Form is hanging whenever I use any dropdown that uses a DataSource. Dropdowns that use a string-based collection do not exhibit this problem.

The basic behavior is this:

1. Start the Program
2. Click a Dropdown that uses a string-based selection, and choose a value
3. Click a Dropdown that uses a DataSource, and choose a value
4. Try to click on any other control, including the Windows Exit control, but there is no response
5. Click Stop Debugger icon to terminate the program

I have done some debugging, and find it strange that after the program finishes with the ComboBox events, it wants to go run some other seemingly unrelated code in my Designer.vb file, then go through all my resources (I use a LOT of graphics in this program, and recently added four larger ones (200 - 300KB), but I can't imagine that would cause this.

Other than the four new images, the only new thing I can think of is that I changed the ComboBox to use the ValueMember property so it would show the Name but return the ID (at least I'm pretty sure that's what it's supposed to do). Please correct me if I'm wrong about this, but also know that setting it back to None does not correct the problem.

Also, if there are other debugging techniques you know of that will help me to sleuth out the root cause, that would be great.

Thanks,
Tony G.

Note: MS Access added as a topic since all my data tables come from a single Access MDB file.