@Jojo Lapin I once read that the shortcuts in OS X are different, but I frankly have no idea about them. Since the OP didn't state until now his OS, it didn't even crossed my Linux-centric mind that that could be the case (though it turned out it isn't).
@mx I really don't know what could possibly be wrong with your installation, as there shouldn't be any differences between Ubuntu and Mint (which is what I use) in this regard. Just to be sure, I went to install the latest release of pd-l2ork (build 20160614) and the shortcuts work properly. On top of that, when you create a new patch then click on the Put menu, you can see the list of things you can create, followed by the shortcuts they use. I see this: