Burger menu button under Game view is overlapping Gizmos dropdown when it is maximized.

Steps to Reproduce:
1. Create a new project
2. Game view > Burger button > Maximize.

Actual Result
Burger menu button under Game view is overlapping Gizmos dropdown

Expected Result:
Burger button is clearly visible.

Note:
Refer attached Screenshots

Reproducible on:
2019.3.0a4, 2019.3.0a3

Works On:
2019.3.0a2, 2019.2.0b5

Environment:
Both Windows and MacOS

NOTE: Same problem present for all maximized windows with a burger menu (so, pretty much all maximized windows)