Today, I was troubleshooting a widget that I created which uses jQuery with the popeye plugin. My masterpage had a reference to a copy of jQuery that I am hosting on a static domain referenced by multiple websites... like using a CDN, but just have a single server.
When in the backend of Sitefinity, they are using jQuery, so there was a conflict loading multiple copies of jQuery and my widget would not display.
See this jQuery in Firefox forum thread on Sitefinity.com
I've decided to reference Sitefinity's copy of jQuery instead, but now the order my scripts were loading is incorrectly. I had been using the asp:Scriptmanager, but doing that seems to result in those scripts loading before the Sitefinity scripts.
I know that sf:ResourceLinks can be used to load local paths as well, but I do not believe that I can load things from my static domain.
Sitefinity's script widget offers the ability to load scripts from another domain and to decide when they load (head, within content, before closing body tag), but I would rather not drag on multiple widgets for a single area of content, since each of those script widgets will show up visually in the back-end.
There is a way to use Sitefinity's copy of jQuery and not have it use $telerik.
It is explained on the Telerik website in a post about jQuery noConflict and jQuery plugins as well as the Sitefinity forum.
This seems to be working fine in Sitefinity 5.0.