Same problem here with Android Studio 1.0 RC2. The Device Monitor shows the application name but in Android Studio’s logcat panel, the package name is always a question mark.
I fixed the problem by Checking Tools / Android / Enable ADB Integration and then restarting adb.
A simpler way to is to Debug any app, if ADB integration is disabled, Android Studio will prompt you to enable.
You have to enable ADB integration to launch debugging. Do you want to do that?
Click Yes, of course.