I like the idea of pcmanfm/libfm being tied in more closely to the lxde components, thus reducing code complexity.
However, using gtk3 for libfm means using --enable-gtk3 for lxpanel as well. That fails with the following error (using todays git versions of libfm and lxpanel):
make: [netstatus_la-netstatus.lo] Error 1
make: Waiting for unfinished jobs....
netstatus-icon.c:29:29: fatal error: gtk/gtktooltips.h: No such file or directory
#include <gtk gtktooltips.h="">