When searching, if you select "author", "journal", etc, then "author:" is going to show up after whatever text has previously been typed in the search bar. Naturally it makes more sense to insert it before existing text, don't you think?
Most people use it as the first thing. So I select author: then type smith and select my next query.
The ability to easily and intuitively create and modify search queries is fundamental to quickly finding relevant papers that you don't already know about. Any chance the Papers 4 search interface might in time include some of the really useful features that were in Papers 3?