Slice button is getting clipped when "Grid By Cell Size / Grid By Cell Count" options are selected from Type dropdown. However, it is not clipping for "Automatic" which is by default.

Step to Reproduce:
1. Create a new project with 2D Template
2. Import any texture
3. Change Texture Type to "Sprite (2D and UI)"
4. Sprite Mode > Multiple
5. Open Sprite Editor Window
6. Click on Slice dropdown
7. Select Type as Grid By Cell Size / Grid By Cell Count

Actual Result:
Slice button is clipping on selecting "Grid By Cell Size / Grid By Cell Count"

Expected Result:
Button position remains same even on selecting options from Type drop-down

Occurring in:
2019.3.0a12, 2019.3.0a3

Working fine with:
2019.3.0a2, 2019.2.1f1

Environment:
Windows 10 and macOS 10.14