Set category: time to complete operation?

[alobo]

When we select a large number of pictures and want to set a common category to all of them
(i.e., trip name for all pictures of a given trip), how long we have to wait to make sure the
category has been set to all pictures? There is no "OK" button and/or message telling the user to wait
or notification of operation having been completed.
Thanks

[xnview]

the category is added when you change the selection