Windows keep coming down after going bumps on road

[cubbyno9]

Hi all,

Hopefully someone can help me with my 1998 Boxster.
When I go over a pot hole or rough road (anything actually) the passenger and drivers windows come down as if I am going to retract the roof. It has only started this weekend.
I retract the lever at the rear view mirror and then reinsert and press the windows back up. It doesn't stay up for long before they come down again.
I take it something is loose or broken with the roof lever ? or could anyone please advise where I should start the investigation or what is causing the problem.

Thanks in advance.

Craig