I check disable cache when dev tools is open but my firefox still caching some javascript. Cmd + Shift + R doesn't affect this behavior. Some files like font are cleared but javascript files seems to still cached for some of them.
When I go to preferences and manually clear the cache it's work. But it's not really efficient.
Also using Web Developer Toolbar to disable cache is working.
Edit : Worked just for times and after a reboot of my laptop it's stop working.
Any Idea someone ?
Updating plugins solved this issue for me.
https://www.mozilla.org/en-US/plugincheck/