Firefox isn't included when 'alt-tab' through apps

When I have multiple open apps - I religiously use alt-tab or ctrl-tab to toggle through them.

However - Firefox is not included in this… the only way I can get back to firefox is by selecting it in my task manager.

I know I’ve done something wrong or need to change a setting… just don’t know where to start with this…

Ah - found the correct setting in ICONS-ONLY TASK MANAGER SETTINGS…