Saab: Cluch Engagement, hands on experience, gears

Question
Occasionally, my 97 900 5 speed will refuse to change gears.  

When this happens, I have the cluch fully engaged and come to a complete stop in gear and the engine won't die but I can't change gears.  I can get it into neutral but won't go into any gear after that.

At this point, I turn off the engine.  I can then change gears to what ever gear I wish.  I can start the car in gear with the cluch engaged and drive normally until it happens again in a few days.

Is there a malfunctioning electroninc switch that disallow gear shifting even though the cluch is engaged?

Answer
Richard:
  I am sorry, but my hands-on experience is limited to the earlier (pre-1993 model 900's) as noted in my profile. I can suggest that you consider subscribing (25/year) to the following site which provides the very best individualized info on your vehicle that I know of.
<www.alldatadiy.com>
   Hope this helps,
                 Jerry