Dom.popup allowed events
From MozillaZine Knowledge Base
To distinguish between wanted pop-ups and unwanted pop-ups, Mozilla applications maintain a list of events that can legitimately spawn pop-ups. This preference is that list.
Possible values and their effects
A space-separated list of events that can spawn pop-ups. See here for a list of all possible events (look for sEventNames). (Default: change click dblclick mouseup reset submit).
First checked in
Has an effect in