Steps to reproduce:
1. Open the project
2. Change the Sprite mode to "Multiple"
3. Click "Apply"
OR
1. Open the project
2. Change the Sprite mode to "Multiple"
3. In the dropdown list of "Texture type", select "Sprite (2D and UI)" (even though it is already selected)
Expected: Sprite mode does not change
Actual: Sprite mode is reset to its default value (Single)
Reproduced on: 5.3.7p2, 5.4.3f2, 5.5.0b3, 5.5.0f3, 5.6.0a5