When I'm trying to add op mode more than 3 users, the mIRC ops only 3 of them.

I select more than 3 users:
http://i.imgur.com/d9KvHkf.png

After I click to 'Op':
http://i.imgur.com/Wn2LltE.png

I know the command(/mode #chan +oooo user1 user2 user3 user4), but GUI is more comfortable. laugh