I assume you are using Firefox on a Mac, am I correct?
The functions that you point out are Windows-only functions because they use a method not supported on the Mac and which draws on features that — if you are using Firefox on Windows — may not be supported there, either.
We are basically a Mac shop here and had to make the decision as to whether or not we’d add a function for Windows users that we ourselves could not use. We opted to give Windows users the feature even though I have never been able to use it myself. (Kathlyn uses both Macs and Windows when she surfs but I only use my Mac.)
As to the 52 million Firefox users, we get very very few Firefox users here at the Cow. (Like you, I use it myself but Firefox accounts for so few users here at the Cow that it is not even in the Top 15 browsers in our site statistics.)
We are working to replace the existing system and so we will not be amending this existing interface. We will be looking at adding this functionality to many more browsers in the new system and will if the ways exist to allow us to facilitate it.
Best regards,
Ron Lindeboom