All right, after having worked through Cocoa Dev Central's "Build a Core Data Application" tutorial I started experimenting with building my own application, using the code and .nib file from the tutorial as a reference to make sure that things are put together properly. Overall I've been managing pretty well with it, however I seem to have hit a snag.
I'm building a form with two NSTextView boxes, like in the tutorial, however linked to different attributes within the same entity. All the other controls work properly and save/refresh their values when I go between records (minus some date box silliness, where the second box doesn't want to save its values). I have checked all of the bindings settings and the NSArrayController against the .nib from the tutorial to see where things could be off; that led to unhooking the first text box and then reconnecting it with the same settings and it suddenly magically working. The second box doesn't want to behave, however, and persists in breaking the program (the debugger shows up, listing all manner of variables and memory addresses and stuff that's frankly quite beyond my comprehension).
Currently, the offending box is configured as follows:
Class: NSTextView
Value: Bound to `history`
Controller Key: selection
Model Key Path: `description`
Checked: Allows Editing Multiple Values Selection
Checked: Conditionally Sets Editable
Checked: Raises For Not Applicable Keys
Any insight into what's going on here?