C1Expander includes the option to specify the expand direction using the ExpandDirection property. In addition to setting how the direction the control expands, changing the ExpandDirection also changes the header's orientation to the content area of the control. By default the ExpandDirection property is set to Bottom and the control expands from top to bottom.

So, for example, in the Aristo theme:

ExpandDirection Setting	Preview
Bottom (default)
Top
Right
Left

You can set the ExpandDirection property in the C1Expander Tasks menu, in the Properties window, in Source view, and in Code. To set the ExpandDirection property in the C1Expander Tasks menu, select the ExpandDirection drop-down box: