[CLIENT] Item search doesn't work

Like the title says, the Search Items in the item sets does not work(sometimes). I just double click the box to delete the text "Search Items" and type something in to get no result. I even tried hitting the x and holding backspace to delete all the text with no luck. "Search Items" text is default inside the box and can be highlighted and deleted(like text) when this bug occurs. After a while though, the box returns to being able to search, and the text cannot be highlighted anymore. I have no idea how to replicate this, as it just happened when I freshly started up league, opened item sets, went to the the map and champion tab, changed the champion to Zilean(through champions I owned checkbox), then went to the item tab, and double clicked search items(as it was text in the search box that I had to delete manually).