Can't always select any category in composer

[awesomerobot (Kris)]

Our default behavior is to scope the composer to the current category, all other categories are searchable, some previous discussion here:

When creating a topic from the specific category, is there a way to only show that parents child categories?

I have 4 main categories. Main, Bugs, Off topic, Misc. In Bugs I have “PC” and “MOBILE”. If they go to the Bugs category and press New Topic, they are greeted with the entire list of categories and child categories and make it difficult to properly tag things when they don’t know any better. I see on this forum it has only 3 categories showing despite there being many. How was this achieved?