Xfce4 buggy touchscreen behaviour (xorg-server 21.1)

In postmarketOS I noticed that some touchscreen actions in Xfce4 behave buggy since the upgrade of xorg-server from 1.20.13 to 21.1.1 on 2021-11-11.

I noticed:

Volume icon in the panel does not open/close on short click. Long click keeps it open.
Same in the Network-Manager icon in the panel. (Well, occationally it remains open.)
Open the Settings Manger -> try to move the Settings window by grapping the window top bar -> the window moves step-wise.

I have not tested it in Alpine Linux. As there is also an upstream bug report, I expect Alpine Linux to be affected, too. I'm not sure if this way of issue reporting meets the philosophy, I hope it's ok to mention the bug here.

Upstream bug report at Xorg: https://gitlab.freedesktop.org/xorg/xserver/-/issues/1255

Downstream issue report at postmarketOS: https://gitlab.com/postmarketOS/pmaports/-/issues/1308

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