xprop has been shipped with Thinlinc since 2004 due to missing features in Solaris's version (Bug 623). We no longer support Solaris, since Thinlinc 4.4.0 (Bug 3614). Hence, we should start using xprop provided by the distributions we build Thinlinc for, to not have to manage it ourselves and keep it up to date.
Shipping our own copy can be a strong advantage, as it reduces the requirements for the base system and hence reliability. More so in today's world, where distributions are focusing on Wayland. X11 utilities are more likely to be missing now.
