Semi-Operable Passenger Window 500SL

The passenger window in my 1990 500SL is now inoperable via the console switch. Over the last year, it seemed to operate very slowly, compared with the speed of the driver's window, but it DID operate. Now that we're in soft-top season, it WILL go up and down when the top is raised or lowered......but, only in conjunction with engaging the top mechanism, with one exception......if I stop the top-down cycle just short of the windows being raised to their full up position.....I CAN use the console switch for the window, but regardless of which way I operate the switch (up or down position), the window will only raise..........curious, but seems related to the integration of the windows and the roll-bar into the top mechanism's cycle........Any thoughts?????