Mac desktop app development issues NSBrowser usage

I set the Browser's Max Cols is 2.
Use a proxy
- (Int) browser: (NSBrowser *) sender numberOfRowsInColumn: (int) column
{}

I found that when first initialized only return the first row of data. The second row is not initialized.

I was not there again is not set? Or? I need a second line of some default values.

Also NSBrowser demo I can not find the relevant official explanation rarely? Seeking recommendations related demo and information

Reply:
The browser in the end how to set the default selected value ah?
Reply:
There are examples ah, search SimpleCocoaBrowser, ComplexBrowser