The Navigator panel menu's Panel Options… is enabled and opens a dialog with
the view box color (a preset or a custom color; Light Red, today's color, is
the default) and Draw Dashed Lines as Solid Lines, off by default, which draws
dashed strokes without their dashes in the panel's thumbnail only. The
options are kept with the UI state, and ui.navigatorPanelOptions sets them.
RenderOptions::solid_dashes draws dashed strokes as solid lines, including
type strokes and the silhouettes of stroke effects.