This happened in one of the recent updates, but as an example on my Sky+ HD remote, there is a keyboard shortcut for the green button which is "Cmd + Shift + Green" (that is what appears when you hover the mouse over the virtual remote).
However, when you actually press this combination of keys, it ignores the fact you have pressed Cmd or Shift and just assumes you pressed the G key. I know this because I can see the "Guide" button on the virtual remote push in, and this key is mapped to the single letter G.
I know one of the recent plugin updates on Mac was meant to fix some bugs with shortcuts, but this one still remains and it would be great if it was fixed as I rely on these shortcuts all the time - not least because I have mapped them to the Remote Buddy software and trigger them via a hardware remote.....net result is the green key (and others) on my remote no longer work.
I am pretty sure this is a very simple fix - but to help Sling on their way, I can confirm that the key combination for Cmd + Shift + Y (which is mapped to the yellow button) works fine - presumably because the Y key is not mapped as a single key to any other button, and thus this single mapping isn't there to take precedence incorrectly as the G key does in the scenario above.