I believe I have seen the same issue in a couple of different situations. Just now it happened as follows:
I opened Formula Workshop and pasted in an equation, which I expected to generate either a true or false result. But PanX stopped responding and most of the menus are grayed out.
The equation I pasted in is:
aggregate({GenCredit},"+",{Invoice=lvinvoice and DT="P"})≠GenCredit
Here is what the menus look like: (These are the signs, if I understand correctly, that PanX thinks a procedure is running and has disabled mouse clicks and greyed out the menus to prevent stray mouse clicks or keystrokes from causing the procedure to fail.)
Eventually, I force quit to escape from this freezing.