keyboard navigation crippled on issue page
For some days now I experience a weird problem when I'm reading the page of a single issue (like this one https://bitbucket.org/tortoisehg/thg/issue/1673/incorrect-behaviour-of-goto-current-rev for instance). (Ctrl-)Home, (Ctrl-)End, PgUp/PgDn, Up/Down keys almost do not react anymore. Mostly no reaction at all; rarely a veeeery late reaction of the keystrokes. Moving the scrollbar with the mouse is the only option left (but not the fastest one). All other pages seem to behave normally. It's not platform dependent, as I experienced it on Win7 and on Ubuntu, using Firefox. (On this page, where I'm registering this issue, all works well too.)
Anyone any clue as to the cause or solution ?