Requirements:

• Primary monitor should be 4k resolution with High-DPI option (150% < X).
• Secondary monitor should be 1080p resolution scaled at 100%

How to reproduce:
1. Open Unity
2. Load user-submitted project(TestUnityProject.zip)
3. Move Unity Editor to the primary screen and make sure the window is adjusted for High-DPI
4. Undock any window in the Editor
5. Move the window to the secondary screen
6. Try maximizing it

Expected result: the window gets maximized on the secondary screen
Actual result: the window disappears

Notes:

• Window can be viewed again by launching Unity Editor in secondary screen or when both monitors are set to same resolutions and DPI settings

Reproducible with - 5.6.5f1, 2017.1.3f1, 2017.2.1p2, 2017.3.0p2, 2018.1.0b3