Inserts a LINK element into the resulting HTML page and applies an external style sheet(s) defined by CssRegistration.
Assembly: Microsoft.SharePoint (in Microsoft.SharePoint.dll)
The CssLink server control resides on the master page while CssRegistration controls may be placed on a master page, page layout, or content page.
When the page is assembled, all of the style sheets are rendered by the CssLink control. If the styles that you define in your .css file are also in Corev4.css or the theme they will be overwritten (typical .css behavior).
Changes made to Corev4.css may be lost when Microsoft SharePoint Foundation is updated, such as through installation of service packs or patches. An alternate .css file can be specified in the ONET.XML file of a site definition by using the AlternateCSS attribute of the Project element.
If the UIVersion property of the Web page is set to 3, core.css will be rendered. If it is set to 4, corev4.css will be rendered.
This is an important distinction throughout the page.
Every reference to corev4.css on this page should be replaced with core.css/corev4.css.