Steps to repro:

1. Create new project;
2. Add Terrain gameobject (GameObject -> 3D Object -> Terrain);
3. In Terrain Inspector hover over 'Paint Details' tab icon.

Actual result:
Tooltip 'Place plants, stones and other small foilage' is displayed (see attached actual.png screenshot).

Expected result:
Tooltip 'Place plants, stones and other small foliage' should be displayed.

Notes:
- Reproducible on OSX 10.12.3 and Windows 10;
- Reproducible in 2017.1.0a6, 2017.1.0a5, 2017.1.0a4;
- Tooltip was only introduced in 2017.1.0a3 so it's not shown in previous versions (5.6.0, 5.5.0 etc), thus not regression.