In VBE properties pane is completely empty and cannot be closed

[ask2tsp]

Starting a few hours ago, when I open an Excel workbook and start the Visual Basic Editor there is a completely empty properties window showing only "properties ******** name>" and the X on top. Clicking the X does nothing.
I use this to change the codename for sheets to address them directly and to give more meaningfull names to modules.

I am using office 365 a few weeks now using cloud storage.

Any idea why this happens and, more importantly, how this can be resolved?

 

[ask2tsp]

A workaround I accidentally discovered: drag the properties window all the way to the left; it docks and then turns normal again.