When any Tile Palette tool is selected then "Focus On" dropdown doesn't expand under the Tilemap panel in the Scene View, Refer attached video

Steps to repro:
1. Create a new project with a 2D Template
2. Hierarchy > Create > 2D Object > Tilemap > Rectangular
3. Open the Tile Palette window
4. Select any brush
5. Scene View > Tilemap panel > Focus On > Select any options(Tilemap, Grid, None)

Actual Result:
"Focus On" dropdown doesn't expand under Tilemap panel in the Scene View when any tool is selected from Tile Palette

Expected Result:
Focus On dropdown should be expanded

Reproducible in:
2021.1.0a3

Working fine on:
2021.1.0a2, 2020.2.0b9

Environment:
Occurring on Windows 10 & macOS 10.15