Definitely still a problem in unpatched 4.16.3-1 in Ubuntu 22.04. Fixed in upstream xfce4-panel 4.16.4 according to announcement (see https://mail.xfce.org/pipermail/xfce-announce/2022-April/001109.html, "Fixed some window buttons not appearing in the panel (#188, !66)"). I hit the bug daily.
Definitely still a problem in unpatched 4.16.3-1 in Ubuntu 22.04. Fixed in upstream xfce4-panel 4.16.4 according to announcement (see https:/ /mail.xfce. org/pipermail/ xfce-announce/ 2022-April/ 001109. html, "Fixed some window buttons not appearing in the panel (#188, !66)"). I hit the bug daily.
Please release new Ubuntu version of the panel package with the patch in https:/ /bugs.launchpad .net/ubuntu/ +source/ xfce4-panel/ +bug/1968942/ comments/ 1 if pulling in the upstream version is out of question.