Returns a `GdkDeviceTool` representing the tool that caused the event.
If the was not generated by a device that supports different tools (such as a tablet), this function will return null.
Note: the `GdkDeviceTool` will be constant during the application lifetime, if settings must be stored persistently across runs, see [ [email protected]_serial].
| this |
a `GdkEvent` |
|
The current device tool |