Notepad++: Ctrl-S does not Save, instead inserts [DC3]; Ctrl-F inserts [ACK]

Ok, this is pretty pathetic. But it's possible some other moron could run into this issue so I feel justified in posting.

A few minutes ago I did a "Replace all" in my current document. Apparently, the dialog window informing me that "# occurrences were replaced" was hidden under another window, so I never closed it.

And apparently, when that little window remains open, pressing shortcut keys with the main editor window in focus causes those funky results.

It's strange behavior, to be sure, but it's still a pretty newb-ish scenario. Ah well.