This fixes an issue where the pref pane would load, QSUserDefinedProxySource would register its notification without a NIB loaded (so synonymName = nil), and then it would perform saves on behalf of whatever control whose editing stopped — like in that case, changing a preset's name. The XIB change is just wiring the control's delegate to File Owner.
… our ivar.
…ad of going though `info`.
I've put a warning in because I want to check that it works, but it never would have worked in the first place (the pref pane was placing image data in the info dict, which QSCatalogEntry was parsing as an image name). We're lucky that nobody ever tried to customize their catalog entries icons ;).
…disappeared. Also giggle the code around so it's easier to understand.