Score Editor

Does anyone use the score editor? Is it just painfully slow or is it me? I've just opened the score editor and I have 15 instrument tracks, and all I've done is changed the "key" in the ruler from "C" to "E", and then tried to hide all but one of the tracks in the score editor. Good. F^king. Grief. That whole process must have taken 20 minutes. It was only blind faith that stopped me force-quitting.