Save as new

Create a new brush. This leaves the original brush unchanged.

Save

Update the selected brush with these changes. If you have edited one of the default brushes, clicking Save creates a new brush in the document.

Close

Any changes apply only to the selected line (if any). This leaves the original brush unchanged.

Notes:

Xara LX saves only brushes used in the document. It discards unused brushes when you quit the program. To ensure a brush always gets saved, draw a line in the gray pasteboard
area and apply the brush to that line. (Items in the pasteboard area are non-printing.)

To edit or add to the default set of brushes, see this page.