boils down to: Borders don't have a notion of enablement, colors and icons are hard-coded.
1) the arrows in the title region are icons in an IconBorder, always the same as set-to/returned from the uiManager. We don't have disabled-looking variants
2) the bounding box around today is a LineBorder configured with the monthView's todayBackground color ... which is null always.
The place those Borders are created, is the CalendarCellContext which is created/used in the BasicCalendarRenderingHandler .. all package private as the switch to painting by renderers isn't yet fully done.
No quick-fix available (except replacing ui delegate and let it return a custom renderingHandler written from scratch, BasicMonthViewVisualCheck in the test package and probably the demos project as well have an example). The 2) could be hacked by letting JXMonthView return the todayBackground conditionally on enablement state.
Need to think of how-to fix it for the longer run. Options:
- make IconBorder enablement-aware, similarly as JLabel greys its icon if disabled?
- add disabled-looking icons?
BTW (and notes to myself):
- the weekOfYear/dayOfWeek separators are painted black always
- the header used for zoomable monthView isn't disabled at all