[GNC] transaction register date-picker pop-up box is transparent, makes choosing dates cumbersome.

[Mike Commissaris]

Recent replies about small register font has prompted me to fix a nagging
issue where the calendar pop-up box is transparent and the text under the
pop-up mixes with the calendar dates causing difficulty picking the date.
The pop-up has focus because I can select the date - just have to discern
the dates from underlying text. I found "dense calendar setting" that can
be placed in gtk-3.0.css (right file name?) but the issue is not with the
calendar, it is actually with the pop-up box transparent background.
Is there a way to make the pop-up box opaque?

System info: Linux - Gnucash all versions 4 and 5 built from tar.gz
downloads
        Kernel: 6.10.8-1-liquorix-amd64 x86_64 bits, desktop: Xfce v:
4.18.1 tk: Gtk v: 3.24.36, Distro: MX-23.4_ahs_x64, base: Debian GNU/Linux
12 (bookworm)
        Desktop: Xfce v: 4.18.1 tk: Gtk v: 3.24.36  Distro: MX-23.4_ahs_x64
Libretto July 31  2023 base: Debian GNU/Linux 12 (bookworm)

-- 
Mike