While it is currently possible to target the first or last item in a RadTabStrip via their CSS classes .rtsFirst and .rtsLast, it is not possible to target individual items, e.g. to add a custom icon or display different background images in tabs.

Assigning icons via the ImageURL property is often not feasible, e.g. when using the RadTabStrip-based navigation controls in Sitefinity.

Numbering the list items, e.g. .rtsLI1, .rtsLI2, .rtsLI3, etc., would be trivial to implement and provide a lot of flexibility through individual CSS targeting.

This also applies to the RadPanelBar and RadMenu controls.