By the way, I did find one minor thing with Openbox 3.5. The Volume Icon was shown twice on the panel, so I commented out the "volumeicon &" in /home/~username/.config/openbox/autostart.sh.
Jeff, thanks for this feedback. I also wonder why I see it twin... :-/
I've discovered how it's happening and a temporary workaround. This apparently has to do with the new XDG-complaint Openbox startup.
After logging in to an Openbox session, this task is running: /usr/bin/openbox --startup /usr/lib/openbox-autostart OPENBOX. The task is started from the last line in /usr/bin/openbox-session.
Looking at the /usr/lib/openbox-autostart script, it first detects whether hsetroot, esetroot or xsetroot exists, then uses the one found to set a background color. It then sets two variables, GLOBALAUTOSTART and AUTOSTART.
GLOBALAUTOSTART scripts are run from /etc/xdg/openbox/autostart or /etc/xdg/openbox/autostart.sh, and AUTOSTART scripts are run from the user's ~/.config/openbox/autostart or ~/.config/openbox/autostart.sh.
XDG autostart stuff is then run from /usr/lib/openbox-xdg-autostart.
The files in the /etc/xdg/autostart directory are all desktop files. For some reason, some of my user-added entries in ~/.config/openbox/autostart.sh were duplicated as desktop files in /etc/xdg/autostart/. I don't know if some openbox update process did this or not. In my user's autostart.sh are the entries:
qasmixer --tray &
The duplicated desktop files are parcellite, wbar, guake and update-notifier. There is also a volumeicon.desktop file there (default installation?). Although desktop files exist for qasmixer and net_applet, they aren't duplicated. I've created a temporary workaround by moving the parcellite, wbar, guake, update-notifier and volumeicon desktop files from the /etc/xdg/autostart directory to another directory. I no longer get startup programs running twice.
Xcompmgr with transparency and shadows is being set by default somewhere. But, I've been unable to find out where.