On an OSX system where there are no mouse connected and only a trackpad is used, scrolling horizontally on a grid with many columns has a rubber banding effect on the content section of the grid.
In Chrome it looks like the column header and the content body is out of sync. On Safari only the content body is affected by the rubber banding effect. Have not tested it in Firefox.
An example can be seen here: http://dojo.telerik.com/azErU/2
Remember that this only happens in OSX when scrolling is taken over by the trackpad. Not sure if this is an issue that Telerik will decide to fix or not, but at least I'll bring it up as it seems to be caused by some overflow CSS.