Update Slate_API.md

Author: Roberto De Ioris

docs/Slate_API.md

@@ -795,7 +795,7 @@ ue.register_nomad_tab_spawner('Hello Nomads !', create_tab)
 
 To spawn the nomad tab you need to search for 'Hello Nomads !' entry in Window/Developer Tools menu. (currently there is no way to place it in other positions)
 
-If you want to spawn (or give focus) to a specific tab, just run
+If you want to spawn (or give focus) to a specific tab (as an example for running it over a toolbar button extender), just run
 
 ```python
 ue.invoke_tab('Hello Nomads !')