There are a few apps that I like to open a fixed point on the desktop each time they are launched. I knew there was probably a way to open apps at fixed coordinates via the Openbox rc.xml, but I couldn’t figure out all the nuances. This is where OBapps3 came to the rescue. It’s in the AUR. I used it successfully to fix the upper left corner of Vivaldi to x=25, y=15 and to always open on Desktop 2. Looking at what OBapps3 has added to rc.xml, future apps can be given fixed coordinates via manual editing if desired.
One problem is OBapps did not automatically show up in the jgmenu. Initially it had to be launched via the cli as obapps. After creating an obapps.desktop file in ~/.local/share/applications jgmenu picked it up the next time the menu was opened.
obapps.desktop
[Desktop Entry]
Type=Application
Name=OBapps
Exec=obapps
Icon=basket
Comment=A graphical editor for Openbox application settings
Terminal=false
Categories=Settings
StartupNotify=true
Lines added to rc.xml
<applications><application name="obapps" class="Obapps" type="normal"/>
<application name="vivaldi-stable"><desktop>2</desktop><position force="no"><x>25</x><y>15</y></position></application>
</applications>
These lines were added at the end of the file and just before
</openbox_config>