I use this add on every day while submitting themes. (I see it is a Legacy addon) Since the 55.0.2 update the eyedropper won’t show up so I can’t use it. I am hoping the developer will upgrade it so it will work. Keeping fingers crossed.
The Tools menu in Firefox already includes an Eyedropper tool that I think should work pretty well.
Oh my Gosh! Thank you. I had never clicked on Developers Tools because I wasn’t a developer! That solves one of my problems!