In the Selection, you can choose the filter effect you want to
use.
It is split in two separate areas; the Filters list and the Stack
list. You can use the Filters list without ever touching the Stack
list, but to get the most out of UnPlugged-X, you'll be spending
time in both. If you only need a single effect to be applied at a
time, you only need to know about the Filter list.
The Selection has two different modes of operation; Filter and Stack mode.
In Filter mode, the Filters list is lit up and only the effect selected in the Filters list is applied. To select the Filter mode you can click anywhere on the Filters list or the vertical label on the left of the list.
In Stack mode, the filters in the Stack list are applied (according to current settings and/or selection). Similar to the Filter mode, clicking on any part of the Stack list or vertical label to the left of it will set UnPlugged-X to Stack mode. In Stack mode the Stack list is lit up to indicate it is enabled.