I am having the same problem. When I upgraded from version 2.5 to 2.7, the jqxExpander is completely messed up.
I have figured out what is causing it — when I use this property:
headerPosition: “bottom”
then the content of the jqxExpander displays (instead of the header), and the expand/contract functionality no longer works.
However, if I set headerPosition to “top” or comment out the property entirely, then the jqxExpander works as expected.
I am using IE8 in compatibility mode (although it functions the same way in IE8 without compatibility mode running), with jqWidgets version 2.7, jQuery v1.9.1 in an ASP.NET 3.5 web application.
Please fix this bug, the users are used to having the header display at the bottom when the jqxExpander is expanded so being forced to display the header at the top is troublesome :/