I seem to have found a "fix." After you quote, when the spacebar isn't working, hit enter. Then backspace the linebreak that enter created and the spacebar should beging to work. I'll install an addon to instruct users in the future.
I use Chrome also so I completely understand. Apparently Firefox has really made some x64 leaps lately so I might be switching back to it at some point. But what I said above should fix your problem if it makes sense.
Honestly, I'm not sure why you're not using 7-zip anyways. It's awesome and only rivaled by Peazip nowadays which I've never tried.
Anyways, let me know if there's any way I can help.