Zotero-Related addons/extensions break Firefox functionality
Recently I have been having a problem with Firefox (50.0): my findbar completely stopped working/showing up. Neither CTRL + F nor Edit -> Find nor F3 would bring up the findbar. As "find" functionality is one of the most useful and essential tools in Firefox (or any other browser, or any other application for that matter), I racked my brains for 4 days trying to figure out why Firefox's findbar suddenly stopped working. In desperation, I disabled all of my addons/extensions (I have many) and then went through a painstaking process of re-enabling one addon/extension at a time and then restarting Firefox to see which addon/extension, if any, was/were disabling my findbar. Through this process I discovered two addons/extensions that, when enabled, either together or individually, kill my findbar: Zotero and Abbreviations for Zotero. I really enjoyed the Zotero-related addons/extensions to my browser, but I need to use the findbar literally hundreds of times per day, so, sadly, the Zotero-related addons/extensions have to remain disabled.
If you're still having trouble, we'd need a Report ID from Zotero for Firefox.
And we have nothing to do with Abbreviations for Zotero, so you can disable that while you're debugging this.
Following the information in the link you posted, the Zotero Error Report says, "No errors have been logged since Zotero started." There is no Report ID to give.
According to information obtained from the Firefox Add-ons pane, the FF "Zotero" add-on version is 4.0.29.16, last updated 11/24/2016.
I know that many Mozilla developers complain about their addons being repeatedly broken as the Firefox API repeatedly changes. I'm wondering whether there has been another API change (or something similar) that affects the findbar when an addon doesn't take the change into account.
In any case, it seems this findbar issue is not limited to Zotero-related addons/extensions.
So this has got to be something more specific than Zotero breaking Firefox functionality. Could be two add-ons together, a theme, etc.
That's why Dan was asking for the error report with no other add-ons enabled.