In the past, the new Kickoff used to be "inverted" when located in a top-panel or in the upper area of a side-panel so that the "Application/Places/Session-Management" area is on top and the search-bar on the bottom of the window.

With 5.23 this behavior was removed and it opens the same way as it does in a bottom-panel.

As i use kickoff mainly for session management (as krunner is as awesome as it is ;) ), i find this change unfortunate, as the session management is no longer right next to the icon i click but more halfway down the screeen.