NSTableViewCell add NSOperation example

Hello,

Please excuse, I may not word this correctly.

I'm trying to figure out how to add a NSOperation to a NSOperationQueue from a NSTableViewCell. My NSOperationQueue has a max concurrent limit of 1 making it a serial queue. But once I click the "Run" button I want the progress bar to reflect the progress and if I click on another row and click "Run" I would like to add it to the queue and show the progress once it starts processing. The best example I can come up with it being very similar to the App Store and running updates.

I hope this makes sense, I could not find anything via Google that made sense. I'm hoping someone knows of an example from which I can study and learn.

Here is a screen shot of the example app ...

Thanks!