Answer by Soviut

I agree that an input dialog would be very handy. In the mean time, you may be interested in some of the solutions for doing modal dialogues here: http://answers.unity3d.com/questions/139677/how-to-make-a-modal-dialog.html It would be nice if you posted your code for the custom editor window as a new answer, just so there's a complete solution available for others when they come across this.