Setup: Running stretch as guest vm on Openindiana (a solaris 11 off shoot) inside Virtualbox
Using lxde desktop, but set to boot into console mode, and I use startx to get to X with I want it. Following a startx, I see the buttons on bottom panel just show a white rectangle with red X in it. I see the image files they point to at /usr/share/lxde/images/ are present. I tried chowning that directory to my user with sudo chown -R reader:reader /usr/share/lxde/images on the off chance there is a permission problem somewhere in that chain. But appears to make no difference It must be some kind of clue that the images are not able to display, but I'm not figuring out what it is.
