Android Studio "design tab" missing [closed]

Question

The "Design" tab in Android Studio's graphical editor, and the preview tab at right, are missing. How can I cause them to appear?

Answer 1

In order to restore the tab, you need to close an xml file, which contains layout and reopen it again within editor. No need to restart android studio. It is, probably just a little bug.

Answer 2

Go to "View" in the top menu and click on "Tool Buttons". The preview tab at the right side should appear after that.