Right-click/paste option grayed out in Youtube, Google, Bing, and others with Speed Dial add-on enabled

I am using Firefox Nightly 73.0a1 (2019-12-07) (64-bit) on Windows 10. If I right-click in the search bars of YouTube.com, Google.com, Bing.com, and others, the option to paste is grayed out. The option is not grayed out when right-clicking the URL bar or comments sections such as this post I an writing now. I have been happily using Speed Dial for a very, very long time. I believe the problem began when Firefox Nightly updated from 72 to 73 just within these last few days. 

I have tried a suggestion I found on a Mozilla forum, toggling "dom.event.clipboardevents.enabled" and restarting the browser, but the problem remains regardless of whether the toggle is in the true or false position, so I returned it to its default "true" position. I shift-clicked on Firefox Nightly to start it in its safe mode, and the problem was gone. I use only nine add-ons. First, I disabled all my add-ons and restarted Nightly normally, and the problem was gone. Next, I enabled each add-one one at a time such that one and only one add-on was enabled and restarted Nightly each time. The problem returned only when I enabled Speed Dial. I enabled all add-ons except for Speed Dial, restarted Nightly, and the problem was gone.

I am able to do a Ctrl-V to paste into those fields where the right-click/paste option is grayed out, but it isn't ideal. I hope this problem is given some attention by the Speed Dial developers.