mouseDown: in a custom NSTextField inside an NSTableView

Had the same problem. The accepted answer here didn't work for me. After much struggle, it magically worked when I selected "None" as against the default "Regular" with the other option being "Source List" for the "Highlight" option of the table view in IB!

Edit: The accepted answer turns out to be misleading as the method is to be overloaded for the table view and not for the text field as the answer suggests. It is given more clearly at https://stackoverflow.com/a/13579469/804616 but in any case, being more specific feels a bit hacky.

It turned out that NSTableView and NSOultineView handle the first responder status for NSTextField instances differently than for an NSButton.

The key to get the label to respond to the first click like a button is to overwrite [NSResponder validateProposedFirstResponder:forEvent:] to return YES in case of my custom text field class.

Documentation:

http://developer.apple.com/library/mac/documentation/Cocoa/Reference/ApplicationKit/Classes/NSResponder_Class/Reference/Reference.html#//apple_ref/occ/instm/NSResponder/validateProposedFirstResponder:forEvent: