Currently annoying but potentially nice Rated 3 out of 5 stars
I liked it because I set a pair of shortcuts for spanish and catalan dictionaries:
"rae:" -> http://buscon.rae.es/draeI/SrvltConsulta?TIPO_BUS=3&LEMA=
"cat:" -> http://ec.grec.net/cgi-bin/AppDLC3.exe?APP=CERCADLC&GECART=
But I uninstalled it because it puts the focus in the addressbar when mouse hovers it, and this results disturbing when you are trying to write something in a form.
The add-on is quite flexible in options; if only it would be a bit more flexible and allowed to disable the address bar focusing, I would install it again.
Thank you and regards!
URL bar fast select
What you are describing is the "URL bar fast select" feature with the options set as not to require any key pressed for that feature to work which do not correspond to default settings, probably you changed them inadvertently. This feature allows you to click on parts of a URL as if it were a button to jump to that sub-part of the URL.
You can put them back to default by going into the QuietUrl preferences and under the Misc tab and group "URL bar fast select" you can select what keys are needed to activate the feature.
Also please next time consider contacting me at the URL reported in the add-on page as "support URL" because I don't get notified by mozilla of these reviews by any means.