The only reason I worked on the checkable/filter sample yesterday was because someone called Markus asked about the code for the Marilyn Video Store sample, in the comments here. I looked at the source code of that sample and then saw that the checkboxes weren't working correctly. So that's how I ended up creating the sample yesterday, so that I'd have a starting point for integrating that into the Video Store sample.
And so I integrated it today and here's how the Video Store sample now looks:

The checkboxes work as you'd expect—check a checkbox and then the movie is added to the list on the right; uncheck a checkbox and then the movie is removed from the list on the right.
This is where the whole sample can be found:
And here's the source structure:

Next steps are to add selection handling, i.e., when a movie is selected in the left window, the corresponding movie on the right should be selected and vice versa. Then, after that, split the application into three modules, one for each window, sharing a third module that provides the domain objects.
Hope it helps, Markus.