fedora might not like you running seamonkey AS ROOT
in particular "su" without the DASH
that will cause problems
you'r really not fully root unless you use " su - "
as i recall fedora 24 has a "launch nautilus as supperuser" in the menu
or use gtksu
there ARE SECURITY!!! checks for running a GUI as ROOT
and HOW did you install seamonkey ?
( that would be the 32 bit !!!! needing the 32 bit plugins )
--- 32 bit !
or the 64 bit "contrib"
that uses the 64 bit plugins without the 32 bit wrapper