i recently installed the latest and greatest opera (my default browser) dev build, and suddenly, i could no longer get the leaderboards to pop up. but firefox (latest nightly) worked fine. i had had the problem before, so i ASSUMED it was an incompatibility with opera's flavor of javascript and the javascript mark uses.
this morning, new dev build, installed, and still couldn't get leaderboards. but another thing, even when i uninstalled opera, i was still getting my regular 15 tabs. so i knew i wasn't deleting my userprefs, so this morning, i manually searched for the directory containing operaprefs.ini, and VIOLA! leaderboards are working again as they should with opera.
great browser. (8