* _NET_WM_PID must be set by the application itself (or the library that it uses to work with X11). If you use GTK+, this is handled for you; if you use a very low-level library then you will need to set this property on your windows yourself.
* AllTray expects windows to stay in existence for it to be useful for AllTray to dock them.
Compliance with the EWMH, combined with not leaving the process group, will ensure that the software will work with AllTray. I'll go ahead and write up some additional documentation on this, as well.
To further clarify my previous comments:
* _NET_WM_PID must be set by the application itself (or the library that it uses to work with X11). If you use GTK+, this is handled for you; if you use a very low-level library then you will need to set this property on your windows yourself.
* AllTray expects windows to stay in existence for it to be useful for AllTray to dock them.
Compliance with the EWMH, combined with not leaving the process group, will ensure that the software will work with AllTray. I'll go ahead and write up some additional documentation on this, as well.