ComboBox does not show inserted item in array

Question

Dear members,
I like to add a new item to my ComboBox programmatically. The idea is, to either use what is already predefined in the list,
or just to enter a new item, which will be available afterwards for selection.
So I created a NSMutableArray MyCat to keep the values, and the ComboBox is bound to an arraycontroller in IB.
When starting the application, I can select items as expected. I can even enter a new item, and the debugging mode
shows me a new entry in NSMutableArray. But this new entry is not available in the list then. How can I "refresh" the list ?
ReloadData is not working...
here are some code nibbles
init- part
        MyCat = [[NSMutableArray alloc] init];
        if (!MyCat) {
            [self release];
            self = nil;
        } else
            [ MyCat addObject:@"Category1"];
            [ MyCat addObject:@"Category2"];
action bound to Combobx, to create a new entry
- (IBAction)add2Cat:(id)sender
    NSString * entry = [sender stringValue];
    if ( ![MyCat containsObject:entry] )
      [MyCat addObject:entry ] ; 
    [sender reloadData];  // does not work

Answer 1

Are you sure the 'sender' in
- (IBAction)add2Cat:(id)sender
is the NSComboBox?  If not, the reload is a noop.
Add this line to check:
NSLog(@"Control is %@", sender);