It’s reporting that the code in the MouseMove event has an error, which naturally triggers every time the mouse moves. You mentioned added Richard's FormLayoutF function - I'm not completely sure which code it is, and actually I'm away from my computer right now, so I couldn't locate it through my phone- but I don't think there should be any code in the MouseMove Event in the first place. Looks like you accidentally put something there, check MouseMove event event and clear any unnecessary code from there.

This has nothing to do with Richards FormLayoutF Form.
PS Rechard, I reviewed  FormLayoutF Form and found why it did not work correctly.
I forgot to put the Public Function OpenFormLayout() into the Global module, it works just fine.
The only question I have, why are the settings not saved.
When I reopen the CutomerListF Form, the setting are all lost.

The error happens when I try to go into Design View.

Have you added =MoveDisplayFields() to the Load event so CustomerListF knows to load the settings when the form loads?

Kevin is right. Saving the layout and restoring it are two separate steps. Once FormLayoutF has stored the control positions, CustomerListF still needs to call MoveDisplayFields when it opens so those saved positions get applied again.

Put it in the CustomerListF Load event, for example:

Private Sub Form_Load()
    MoveDisplayFields
End Sub

Or, if you are using the event property directly, use:

=MoveDisplayFields()

Also make sure the code that saves the positions is actually being run before you close CustomerListF.

The MouseMove error is a separate issue. As A Toykan pointed out, MouseMove fires constantly, so any error in that event will keep popping up every time the mouse moves over the form. Open the MouseMove event for CustomerListF, find the exact line that fails, and fix or remove that code if it does not belong there.

I would also go into the VBA editor and run Debug > Compile. That will often catch errors hiding elsewhere in the form's code before they surprise you at runtime.