I\'ve just installed an update to android studio and now I see version 3.0.1
When I look to a toolbar I see that icons became two times smaller than usual.
Have the same issue after updating to 3.0.1. As of Google Issue Tracker, it seems like a known issue & it is in assigned state. For a temporary fix, we can adjust the UI font of Android Studio from settings as below.
Note : The above steps will make the Android Studio UI ugly but until a patch is released, we might need to adjust to this.