Under opensuse 12.1 I could type in kwrite and the editor would run. Under 13.1 when I type in kwrite the accessibility application will run. I’ve just realized this morning that I am typing in kwrite and hitting enter BEFORE the launch application can parse the request and find kwrite, this process worked fine under 12.1. I believe this is the cause, if I just type k the accessibility function will be at the top of list. I’m assuming the search is processing the k then seeing the enter and drops the rest of the command entered.
Well, I think the problem here is, that “ENTER” is not related to Kickoff’s search field at all, it is a shortcut to launch the currently selected entry (you can browse the menu with the keyboard).
In your case, the wrong entry was still selected because the search was slower than your typing, so that one got launched instead.
Not sure if that would even count as bug.
Btw, KRunner (the Alt+F2 dialog) is plugin based, it contains runners for a lot of different stuff, like shell commands, menu entries, open windows, browser bookmarks, and can even do mathematical calculations.
Click on the wrench symbol to see and enable/disable the plugins.