Last week i updated ADT from perfectly working v12 to v15. Now my graphical layout editor is broken in eclipse.There are few good thing comes along with it.
Few good thing happened is the compiling method is changed. Prior to v14 when ever we save a file or build a project eclipse build chain will compile all resources like layout ,drawble etc . then compile all java class to class files then dex them to dalvik executable build apk from it. This usually take a little longer if you have big project. New ADT doesnt make apk while building instead apk creation is only when you try to run the application in emulator or device.
Another good thing is compiling Library projects. earlier it was like we need to have full source of library project for referencing it from a main project. Now library project is compiled and packaged to a jar file , you can add this jar file to your main project build path. The only issue is that resources wont be included in jar file. Android recommends not to use any resources in library project