No palette for changing brush, pen, colors, eraser

[milleron]

I'm still using a couple of 9th-gen iPads that work with Pencil 1. At some point, they have lost the ability to display the palette that should appear when annotating a screenshot. The pencil works, but there's no way to change color, brush width, brush, or, worst of all, no way to access the eraser. All those options are stuck on the way the annotation function was configured before the palette broke. The icon for displaying the palette is there, but tapping it does nothing but turn the Apple Pencil on and off. Restarting the iPad didn't rectify the problem

I can find nothing in Settings that might affect the drawing/annotation control