X11 (Xquartz) v.2.3.x has several preferences to sync between OS X Pasteboard and X11 CLIPBOARD and PRIMARY buffers.
While testing 0.46+devel rev21339 I noticed that in Inkscape copying/pasting to/from the clipboard always resulted in bitmaps with all vector information lost (no Paste Style, Paste Size possible) - restoring default Inkscape preferences didn't help.
It seems that the X11 preference 'Update Pasteboard when CLIPBOARD changes' somehow prevents Inkscape from keeping vector information in the clipboard even when ^C/^V objects/shapes in one drawing or between 2 windows.
Unchecking said option in X11 disables clipboard xfer from Inkscape to native OS X applications and restores full Inkscape functionality.
Can someone verify on a updated system (10.5.6 with X11 2.3.2 or 10.5.7 with X11 2.3.3) if the 'out-of-the-box' installation disables Inkscapes native clipboard functions? I could not find related infos in Inkscape Wiki or launchpad answers/bugs.