ToolbarTabChangedEvent

I want to change my layer theme when the user selects a toolbar tab. I'm trying to use the ToolbarTabChangedEvent in an Essentials Workflow, but it is unclear to me how to get the name of the newly selected tab out of it. I need it to know which layer theme to select based on this name.

 

 

JSON of the event argument seems to be empty. Does anyone know what to do?

 

 

Thanks

 

Wout