Because putting : is searching for the stickers , if you put : and type something, it searches for the stickers about the thing you typed, this is why it lags.
so i noticed recently whenever i add a : in memechat followed by a word or icon for emoticons, it gets extremely laggy for a second, which sometimes causes the message to not send and i have to close and reopen the page. is it just me, or is there a problem with the meme icon function?