Small Patch: Better Handling of Empty Params
By way of explaining "empty parameters", consider the following macro:
/cast [combat] Arcane Barrage;
As the interpreter will tell you, this is command will pass Arcane Barrage to /cast if you're in combat. . . and nothing to /cast otherwise. Sometimes this is desirable (clearing your target, for example), but 99% of the time its a bug in your macro.
I've gone back to ensure that handling empty parameters is consistent across all commands. Please drop me a comment if you have any problems.