Inserting ''Special characters'' from below the edit box in LQTs (as used here) does not work in Firefox (latest)

Inserting ''Special characters'' from below the edit box in LQTs (as used here) does not work in Firefox (latest)

There is a box Special characters: below the edit window. When clicking on such a character nothing is inserted; neither in the edit window nor in subject line. If the Search terms-field (on top of the page) had focus before, it is inserted there. I've unchecked all Beta features in Special:Preferences#mw-prefsection-editing and I am blocking advertising (a node [p-googleadsense] and a JavaScript [show_ads.js] are blocked). There is no error in the JS console.

RE rillke questions?21:58, 17 April 2013