I have a NSOutlineView which loads data from a data source. The table is displayed in a panel.

The items shown in the table are items which belong to an object (the relation is one-to many between the object and the items).

I have a list of objects in a combo box (in fact a NSPopupButton), and when I select another object in the combo box, I want it's items to be shown in the table (the NSOutlineView).

I managed to do all this , however when I select another object from the combo box, not all of it's items are displayed. I have put some logging messages in the data source and it seems that there are some items that are being returned from the data source , but are not shown in the table (and are not queried for children).

Now the strange part is that when I click the main window (as I said, all that I described here is in a NSPanel loaded on top of the window) , all the data is displayed correctly. It seems as if clicking the main window triggers something in the NSOutlineView that makes it display the missing items, but I can't tell what it is.