Okay, I more or less figured it out (and did most of the transfer manually), but as it turns out even Opera.Next improves significantly on the forum-situation. Still some problems, but this really helped. So: a good suggestion and much appreciated

@linuxmint7 - Is there an easy way to migrate all/some extensions to "developer" in one easy go?

@linuxmint7 - That's an interesting suggestion. I will have to try this. Thanks!

PS I tried disabling "everything", but that' didn't bring the necessary "relief" either, sadly...

Well, having tested this whole "non-existent" problem some more, I can safely say Opera 24 is having definite problems with several websites running different forms of forum software. As I am a moderator on two forums I probably will have to change browsers once more, which is too bad, cause I was starting to adapt to "new" Opera.

And by "Opera specific" I mean "Opera 24 specific", obviously...

As I am experiencing some serious slowdown issues after the update to Opera 24,
I was wondering if it is possible to "rollback" the update to (for instance) Opera 23
and how I would have to proceed to do so while keeping all my personal settings intact.
That way I could rule out if this is Opera specific.