I am using Windows 10 on a laptop; ArtRage Vitae paid/full version.

This problem happened once before: I start the program, the brushes show up on the canvas when selected, (except for the paint roller and
the custom brush), but nothing happens when I draw the tool icon across the canvas. Starting a new document does not change that.
Opening and using a previous version (AR 4, 5, 6) works fine. As soon as I open these older versions, the brushes work fine,
all are visible on the canvas as I work with them. To get around Vitae's problem I have to restart the program. Then the tools return to
expected behaviour.
No error messages, no other indication. The brushes produce nothing at all, though the cursors move across the canvas
as expected (except as described above).