I don't know when, but think since I upgraded Android Studio to v3.0. As you can see in the screenshots, the screen has divided to 2 equal parts (left and right).
Usually, when the page has no complex or animated objects, everything is OK. But when you want to switch between activities or when the activity has complex and animated objects, one side of the screen (usually left) shows some mixed disordered pictures of the now and even of the past (and usually upside down)!
Other example (in the Browser):
I tested it on various emulators (with the different system image and different screen resolution). Even I completely uninstalled my display adapter driver (Intel HD 4000) and reinstalled it. The problem persists anyway.
Also, I completely deleted the .android folder (which contains avd folder) and two its brothers (metrics folder and the file: analytics.settings) and open Android Studio (to recreate them), but nothing changed.