1. Open Unity Editor -> Project attached (or any other non-new project).
2. Collapse Editor it. Wait for a while (or put your machine to sleeping) (some floating magic happens here).
3. Expand Editor.
Actual result: Editor window is corrupted (see screenshot attached). If you maximize/minimize/click on windows in Editor they'll return to normal state.
Expected result: No corruptions, Editor looks as expected.

Is not reproducible in 5.3.2f1.
Reproduces since 5.4.x.