If I press backspace, sublime will delete both spaces. This might make sense at the end or beginning of a line, but does it make sense in the middle of a line? Perhaps it does, but I find it annoying more often than not. Also, it looks like this depends on the tab size as well. For instance, if the above code is indented 0 or 2 spaces, you won't see the problem. This probably also means it is a bug.