The latest source code of next generation pcmanfm, aka pcmanfm2, in git repo already supports desktop management. The new desktop manager looks better than the old one in pcmanfm 0.5.
RTL is not yet handled, but it will be fixed in final release.
Icons are not yet movable, but it will be supported in next major release
Trash can is not yet shown on the desktop
Tools drawing on the root window might not work correctly since our desktop window covers the root window. However, using a window covering the whole screen space to implement desktop management feature is suggested in freedesktop.org specs, and this is what Gnome and XFCE did, too. So, it’s not a bug.
Please test the latest pcmanfm and libfm in our git repo. The first public tarball release is coming soon!