XnView Software

When searching for categories it would be nice if the list filtered to show only categories that contain the search term (or begin with/end with, depending on your settings).

Lightroom works this way, and it makes it easier to find the keywords. Especially operations like moving them becomes easier when just the relevant tree items are shown, and not a long list of hundreds, of thousands of keywords/tags/categories.

+1 it would be so useful when using regular expressions. But also show subcategories (or option for it) or grey out those what do not match search and aren't subcategories.
Because for search, among Actions, now we have only Open Tree.

Also, very well done with XnViewMP's categorization, but there's still can be done a lot of improvement and it may take ages for this amount of people. So it would be so nice if we could write plugins, at least for everything related with categorization, and share it here:

• add custom ratings (assign more than one digit value for every file);
• add more labels and split into their own categories (for now we can edit only names of 5 labels);
• add more complicated Categories Filter (when viewing library, not when assigning categories), because just "Match All" or "Match Any" isn't enough.