Lets say I want to use the category "Firefox" for my new blogpost, wich is a already existing category. In earlier versions of WordPress I could just type the word "Firefox" in the textfield and add it. But in WordPress 3.0+ I have to manually find the catergory "Firefox" and choose it.
I have about 330 categories, so it takes time to find the right category and manually choose it.
I want the old function back, please! :)