Option to suppress Firefox's middle-click protection

[ssokolow]

Now that TiddlyWiki/TiddlyWiki5@df6436a has restored the equivalence between ctrl+click and middle-click in TW5, there's a feature mismatch between Chrome and Firefox which can only be solved in privileged code:

Firefox prevents sites from redefining "middle-click = new tab".

Approaches to bypass this were briefly discussed in TiddlyWiki/TiddlyWiki5#462 and TiddlyWiki/TiddlyWiki5#463 but any unprivileged mechanism which would bypass that would do more harm than good by killing off all sorts of other link-related functionality (copy permalink to clipboard, "open in new tab" as a context menu entry, etc.)

The simplest solution to restore feature parity would be for TiddlyFox to have an option to catch the middle-click in privileged code when the site is detected to be a TiddlyWiki, suppress the default behaviour, and then dispatch a click event into the DOM to match WebKit's behaviour.

(I'm not an extension developer but I seem to remember a Planet Mozilla blog post from a year or two ago mentioning an API that makes it trivial to add simple preferences like checkboxes to about:addons entries.)