Cocoa - Reloading NSComboBox (OSX)

Question

::edit - solved.. I had not conformed to NSComboBoxDataSource properly..

I have an NSComboBox implementation that works - except - when the data source is changed, the changes are not reflected in the combo box until the app is restarted. I have [myComboBox reloadData] plastered all over the place, but this is not effective. Any ideas what I should look for?

The data source is marked in IB:

The following data source methods are implemented:

- (NSInteger)numberOfItemsInComboBox:(NSComboBox *)categoryCombo{


    //NSLog(@"categoryMutableArray count: %lu", (unsigned long)categoryMutableArray.count);
    return categoryMutableArray.count;
}


- (id)comboBox:(NSComboBox *)categoryCombo objectValueForItemAtIndex:(NSInteger)row {
    //NSLog(@"%s", __FUNCTION__);

    [self refreshCategories:nil];

    currentCategory  = [categoryMutableArray objectAtIndex:row];
    mainCategory.stringValue = [currentCategory valueForKey:@"catName"];

    return mainCategory.stringValue;

}


- (void)comboBoxSelectionDidChange:(NSNotification *)notification {
    //NSLog(@"%s", __FUNCTION__);

    currentItem = [mainMutableArray objectAtIndex:rowNumber];

    //[self.mainCategory setStringValue:
    // [NSString stringWithFormat: @"%@", [categoryMutableArray objectAtIndex: [(NSComboBox *)[notification object] indexOfSelectedItem]]]];

    currentCategory = [categoryMutableArray objectAtIndex: [(NSComboBox *)[notification object] indexOfSelectedItem]];
    NSString *newCatString = [currentCategory valueForKey:@"catName"];

    [currentItem setObject:newCatString forKey:@"category"];
    [currentItem saveInBackground];

    //NSLog(@"new category name may be: %@",[currentDream valueForKey:@"category"]);
}