Which tool is active in the editor.
| View | The view tool is active - Use Tools.viewTool to find out which view tool we're talking about. | 
| Move | The move tool is active. | 
| Rotate | The rotate tool is active. | 
| Scale | The scale tool is active. | 
| Rect | The rect tool is active. | 
| Transform | The transform tool is active. | 
| Custom | Any tool that is not one of the built-in tools. | 
| None | No tool is active. Set this to implement your own in-inspector toolbar (like the terrain editor does). |