Oh man that's a bummer Diki. Is it just the "push to enter" functionality, or does it ignore scrolling too? You could try spraying some aerosol Electrical Contact Cleaner into the wheel assembly. Let it dry thoroughly before turning the module on. Was it dropped or mishandled? I imagine that this problem could also be caused by a broken solder joint or a broken wire.

BK-7m have now become rare and expensive enough to warrant consulting a good electronics tech (which I am not!) Definitely following this thread, as sooner or later we'll all have to deal with this issue.