[Remind-Fans] Tkremind: Go to previous/next month indicators shown as boxes

[Gary Johnson]

I have TkRemind running on two Ubuntu systems.  On one, the "Go to
previous month" and "Go to next month" arrows on either side of
"Today" appear as arrows, as I would expect.  On the other, they
appear as empty rectangles.  How do I fix the latter?

I suppose it could be a font issue, but I would expect it to work
out of the box on the new system as it did on the old one.  There
are too many fonts to choose from on the new system for me to go
through each one.

The system on which the arrows appear properly has:
    Remind version 03.03.00
    Xfce4 version 4.14
    Ubuntu 20.04.5

    I don't know how to determine the font used.

The system on which the arrows are rectangles has:
    Remind version 04.02.00
    GNOME version 42.4
    Ubuntu 22.04.1

    # Font to use in calendar boxes in Tk font format
    CalboxFont {-family {DejaVu Sans Mono} -size 10 -weight normal -slant roman -underline 0 -overstrike 0}

    # Font to use in calendar headings in Tk font format
    HeadingFont {-family {DejaVu Sans} -size 10 -weight normal -slant roman -underline 0 -overstrike 0}

Both have:
    LANG=en_US.UTF-8
    tcl version 8.6
    tk version 8.6
    wish version 8.6

Regards,
Gary