Can't Drag Pop-Up Nav Form (1 Viewer)

Hi

I have a tabbed navigation form which is set as a pop up but, for some reason, I was able to select and drag/reposition it on the screen until today. I've not changed any positional property settings in the nav form or sub-forms so I can't understand why it's started to behave "glued" to the centre of the screen. Unless I've accidentally changed something I'm not aware of.

Auto Center is set to Yes as this is where I want it to launch. Movable is also set to Yes.

Does anyone know what could cause the form to be locked in position?

Hi. If you create a similar popup form from scratch, can you move it? If so, you could try comparing their properties to see if there's anything different there.