Upgrading to 12.04 caused some problems to my Firefox.
It seems like that Firefox doesn't know how to handle downloads.
After some researches, I've found this solution :
Kubuntu 12.04 Firefox and Rekong don't know how to open downloaded files
but it still doesn't work as it should, in fact it opens my mp3 with Audacity and not with the default player.
But the worst thing is that "Open folder" opens Gwenview instead of Dolphin!
Suggestions?
Best Answer
On Kde, a different approach not involving direct editing. Took it from the link Miguel Aguayo gave in his answer. Someone attached that answer at the bottom in 2014.