When the terrain is modified the brush needs to be reselected in order to change the brush settings. Texture painting does not work.

Steps to reproduce:
1. Open attached project
2. Open the main scene
3. Select the terrain
4. Paint/Raise/Lower the terrain

Expected result: Terrain is raised/lowered/painted on
Actual result: Terrain texturing does not work, raising/lowering it keeps the same settings until the terrain is reselected

Reproduced on: 5.5.0f1, 5.5.1f1, 5.5.2f1
Working width: 5.6.0b8, 5.4.4p4