Has anyone experienced the following in VV3.0a?

Every once in a while, Vegas will cease allowing me to zoom in or out [via KB shortcut or icon] until I close the program and re-open. I can't seem to find any correlation of activity on my part to this bug.

Is this known by SF? Anyone else found the cause?

I'm running W98SE with a vanilla ATI RagePro 4MB AGP card, PIII.

TIA