Fujitsu ScanSnap S510 Operator's Manual page 168

When the [Settings] buttons of a selected action is clicked, the selected action
background color changes to yellow, and other actions become unselectable.
HINT
To select another action, first close the "Scan2Print - Options" dialog box, and
then click on any point in areas other than actions, or place the mouse cursor on
the selected action.
CLICK!
⇒
The selected action background color is changed to the original color (blue)
and other actions become selectable.
6. Click [Scan2Print] in the Action List.
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