I've searched for a solution, too, and found that as well. It is not helping for me.
Btw, I can copy to notepad, too, by Ctrl+C Ctrl+V (not by the middle mouse button. Offtopic question: is there a way to costumize the behaviour of the middlebutton pasting in Ubuntu?).
(Ubuntu 7.04, Gnome, 32-bit)
I've found this: make a file ~/.wine/config and put there
But did not help either. Is there a config file of wine somewhere that i can try to edit? The search tool did not find any.
WINE REGISTRY Version 2
"ClearAllSelections" = "1"
"PersistentSelection" = "0"
"UsePrimary" = "1"