there seems to be a bug with opera 11.60 and duplicate extensions being allowed to be installed

in the past, im pretty sure if i installed an extension from the opera extensions page,
and then installed a newer version of the same extension from the extension authors homepage, the new extension would overwrite the old one.
this doesnt seem to be the case anymore...
with opera 11.60 when i try this, it installs the extension in parallel with the old one, which means there are now 2 versions of the extension installed at the same time.

the id in the config.xml of both versions of the extension is the same, just the version number and author tag are different.
this seems like a bug to me, has anyone else experienced this?

Update
----
i actually tested this with two extensions with the same version nubmer, one was on the opera server's extensions page, and the other one from the authors homepage, exact same version number and id in the config.xml, only the author tag is different. the same behaviour occured, instead of one extensions overwriting the other, they install side by side... definitely seems like a bug to me...

Further Update
-------
I also just tested this in "opera next" v12.00 alpha Build 1191 and the same behaviour occurs there too.