[ATTACH=CONFIG]15323[/ATTACH]
I have this problem too! It is driving me nuts. I can't consistently select even ONE record from a table by clicking on it. Sometimes it works like it is supposed to, and sometimes it does not. When it doesn't work, the record is still blue like it is selected, but the number at the bottom will say "0/73 selected" or whatever (see attached). I always have to double-check that the record IS selected, and doesn't just LOOK like it is, because I can't count how many times I have gone to calculate one selected record and ended up calculating the entire field. So frustrating.
Behaviour is the same whether I am in edit mode or not. I can right-click and choose "Select/Unselect", but I have to choose it twice (first to unselect - even though it was not selected, and then again to select), and I can only select one record.
This behaviour was first noticed in 10.0. I had hoped 10.1 would resolve it but installed yesterday and it appears to have the same issue. Closing ArcMap may or may not help, same with a reboot.