Using a simple RadGrid that has many columns, I am unable to set the header background color using HeaderStyle-BackColor="Blue" in the <telerik:RadGrid tag.
If I have header column name that span one line, the top line it the default light gray color eaeaea from WebResource.
If I have header column names that span two lines, the top line it the default light gray color eaeaea from WebResource, and the bottom line is Blue.
It is rendered in HTML as inline ... <th class="rgHeader" style="background-color: blue;" scope="col">.
I am using v2015.3.1111.45
I can reproduce this buggy behavior in a new project with a basic Radgrid using Northwind in IE and Firefox.