A lot of times when I'm working on the 2.5 mac version, I press tab with no tool active but the coordinate-field/command-bar is not highlighted and I cannot write commands. Also, sometimes, i have a tool active, for example extrude, and i type a value but the tool options field is not highlighted either. I know if i press the minus sign before the numeric value when a tool is active, it doesn't work in the 2.0 version (or older), i don't know if this is a feature or a bug.