Continuing the discussion from Not able to change category if I start a new topic from a specific category:
If this is the behavior we want by default (impossible to change category if the topic is opened in a specific category) then the “Search…” field should be invisible when the category does not have subcategories
instead of giving a “no matches found” result.
Not finding matches, when in reality there are no matches only within that specific category, could confuse users, especially those newly subscribed
Alternatively, in this context specifying the text a little better we could avoid creating confusion, e.g.: “No matches found in the {%category} category”