The settings for panel.usertext are taken from
trellis.par.get("user.text"), but default to
trellis.par.get("add.text") if undefined.
"user.text" is preferred to "add.text" for annotations
because the latter also applies to strip text and key text.
The settings for panel.brushpoints are taken from
trellis.par.get("brush.symbol"), but default to
hard-coded settings if undefined.
The settings for panel.brushlines are taken from
trellis.par.get("brush.line"), but default to
hard-coded settings if undefined.