You need to replace it with something built from the ground up. Apparently Conitec was not prepared or able to do this, so someone stepped in with GED. However, that never was fully realized and the end result is that GameStudio ended up with two editors ... one that is old, clunky, slow, and another that is not really completed.

It's a shame, really, because GameStudio has a long history, (had) a loyal following, and, in the right hands, could have continued to be something really amazing. There's still a lot that could be done with GameStudio v8, but it gets more and more outdated every day ... and it's not fun (anymore) working in either of the editors.