DB9 quarter window dropping

[bloodfire]

Wondering if anyone can help.

Over the past couple of days whenever I drive my driverside rear quarter window drops down and raises again (sometimes not fully) intermittently.

any ideas why or how it can be fixed?

thanks

[Gdc]

I'm no expert but had this fault on a merc convertible and it was a software issue fixed when the software was updated to the latest version