I never understood a developer’s obsession with “their way” but anyways. Thunar is a good light file manager that has one issue, it insists on displaying a warning when being used as root that cannot be turned off. Well I run my personal laptop as root and I don’t really care what others think about it and why it might be a bad thing(TM).

In order to remove the damn warning you need to grab everything needed to rebuild the package from:

http://mirrors.slackware.com/slackware/slackware-current/source/xfce/Thunar/ (32 bit) or http://mirrors.slackware.com/slackware/slackware64-current/source/xfce/Thunar/ (64 bit)

After that download this patch to the same folder and replace the slackbuild with this one.

OR simply clone the git repo and build there.