[X4U] Where do they come from?

[Paul Moortgat]

When I select "remove individual cookies" in Firefox 11 a window will open and showing a lot of cookies.
Then I clear all the cookies, but when I select "remove individual cookies" again, all these cookies are there again.
In that cookies window is a column 'Site' and a column 'Cookie Name' and in front of the name is an horizontal triangle.
When I make that triangle pointing down I can read 'dummy' in cookie column name.
Where do all these cookies coming from?
But when I leave that cookie window open there hardly is a cookie added.  Weird.

Paul Moortgat