Unified player settings window distorts on shrinking it horizontally or vertically

Minimum height and width is not set for unified player settings window. The components in the window become unusable as they are hidden.

Steps to reproduce:
1) Create new project
2) Edit > Settings
3) Drag the unified player settings window horizontally or vertically.

Actual result: Observe that there is no minimum height or width set for the window
Expected result: The components in the window should be visible and remain usable.

Occurring with:
2018.3.0a6 (13fac50c9eea) , 2018.3.0a5, 2018.3.0a4

Note:
Unified player settings are introduced from 2018.3.0a4

Environment:
Windows and Mac