Static Window Close Index
These options are used to either Disable or Enable the CLOSE button on the stats Index window.
The stats Index window is a small window with buttons that when selected display the stats Attribute, Group, Combat, Spell, etc windows. This option gives you the ability to temporarily close the window if needed by enabling the CLOSE button in the upper right hand corner of the window.
Index window with CLOSE button disabled is shown below.

Index window with CLOSE button enabled is shown below.