Hi, Luqqi, and welcome to K-Meleon!
This is not a K-Meleon bug.
I have done a Search for you:
Forum search for "facebok", search the last 90 days:
(You can find "Search" in the top menu of this page. If it's not there, click "Forum List", and it will be a menu item on that page. After entering a search, scroll down for the "age" setting. Works best (only?) for single word searches)
Cheers
SoerenB
Back again ...