Custom brush list preview in terrain paint menu doesn't update when custom brush settings are changed

Repro steps:

1. Select the terrain
2. Go to the paint terrain tab
3. Create a custom brush
4. Change the settings of the custom brush (down arrow next to custom brush name)

Expected result: the brush preview in the list of brushes should change when you change the settings
Actual result: the brush preview in the list of brushes never changes unless you select the brush's file in the project window

License type: Pro