Why is the option Create Filter Transformation grayed out in Spotfire 10.1?

Why is the option Create Filter Transformation grayed out in Spotfire 10.1?

After selecting few filters, right clicking on the "Filter Panel' displays a menu but the "Create Filter Transformation" is grayed out. In order to resolve this issue, you will have to right-click only on those filters where you have made some filter selection.

Example:  As illustrated in the video below,  if you made some filter selection on column "Region" you will have to right click only on "Region" to see the "Create Filter Transformation" option enabled.If you right click on "Income Group" column the option will be grayed out.