The selector scanner is not finished yet, but is now a working feature.
First place the caret  between the opening and closing braces of a selector or identity definition.
Select the scan selector tool in the menu Tools->Scan selector (Alt-T-s).
The current declaration is scanned and shown in the list at the top of the side panel (See the Section called The side panel in Chapter 2).
Edit the values by either:
Clicking twice the Value column to edit directly the value.
Double-clicking the down triangle facing icon in the third column to choose the value from a pop up menu.
It is planned that this list will be a drop target for the CSS tree view to quickly insert or replace new property/value pairs.
The caret is the blinking line that shows you the location of the text insertion point.