It would be nice to have a cancel button on the interface editor along side the done button.
That would be a Button. Those exist already.
In response to Kaiochao
People keep failing to understand...
Currently in the interface editor there is a done button but no way to cancel so unless you feel like undoing a bit you can't cancel the changes you made.
In response to Chowder
And you keep failing to elucidate. There's a reason people can fail to understand something. A, you fail to explain your idea properly, or B, that person is retarded.

All you asked for was a "cancel button." You gave no detail whatsoever. If you want to "undo" your changes, just use "undo." That exists too.
In response to Kaiochao
Why did you bother suggesting to me a method I mentioned in my last post? Yes there is an undo button. I know that...
I'm sorry you failed to understand what I meant by "on the interface editor". It really shouldn't need further elaboration as its a very simple request. It has just been modified slightly to make it clearer for your sake.
In response to Chowder
I understood him just fine. And a Cancel button wouldn't hurt.
EDIT: It also for some reason says "New Window" on the title bar, even when its not a new window =P
I don't know what Kaiochao's problem is, but I understand what you mean. I'd like a Cancel button as well so I don't have to go back and fix a bunch of stuff in case I mess up the interface.
In response to SuperAntx
In response to Falacy
Your right that should probably say the windows name. Do you know if there's a way to reposition a pane window in the interface editor? I can only get it to move around when it has a title bar.