When enabling gizmos via the tile palette toggle, gizmos are only shown for a brief moment.

Steps to reproduce
- Open the attached project in Unity 2020.1.0a14
- Under Assets > Palettes, double-click "Test Palette" prefab
- Select "Layer1" child in the prefab hierarchy
- Observe attached "Tilemap Gizmo" script in the inspector
- Open "Tile Palette" window under Window > 2D > Tile Palette
- Ensure the current palette is "Test Palette" and Active Tilemap is "Layer1"
- Click on "Gizmos" button within "Tile Palette"
Notice issue >> Gizmos are only displayed for a brief moment.

Tested
Windows
Unity: 2020.1.0a14
Package: 2D Tile Map Editor 1.0.0