Superfish WindowShopper steals .dialog(), resulting in exception Object [object Object] has no method 'dialog'

Superfish WindowShopper steals .dialog(), resulting in exception Object [object Object] has no method 'dialog'

The following error appears on my website, when I want to show a dialog:
  • TypeError: undefined is not a function (Chrome)
  • Error: TypeError: $(...).dialog is not a function (Firefox)
This is due to double including jQuery.
The second one is not from my website, but included by the adware WindowShopper in the browser of some visitors.
How to prevent this error?

Example in jsFiddle: http://jsfiddle.net/fybJ3/

[I asked this question on Stackoverflow but got no responses]
http://stackoverflow.com/q/24045676/3708485