1) A simple wrapper bash script that can be used as a startup app instead of Franz - e.g. ~/.bin/Login-Franz
#!/bin/bash
# Start Franz
"/opt/Franz/franz" &
sleep 3
# Get the WIDTH of screen
SWIDTH="$(xrandr | grep " connected" | grep "[0-9]x[0-9]"| cut -d ' ' -f 4 | cut -d '+' -f 1 | cut -d 'x' -f 1)"
# Get the HEIGHT of screen
SHEIGHT="$(xrandr | grep " connected" | grep "[0-9]x[0-9]"| cut -d ' ' -f 4 | cut -d '+' -f 1 | cut -d 'x' -f 2)"
# Get the WINDOW ID of Franz
FWINDOW="$(wmctrl -l | grep " Franz$" | cut -d ' ' -f 1)"
# Calculate the window LEFT position for 750px width
FLEFT="$(echo $(( $SWIDTH-750 )))"
# Calculate the window HEIGHT below a 22px top panel
FHEIGHT="$(echo $(( $SHEIGHT-22 )))"
# Move and resize Franz window as above
wmctrl -i -r $FWINDOW -e 0,$FLEFT,22,750,$FHEIGHT
# Close Franz window to system tray
wmctrl -ic $FWINDOW
exit 0
Note: Some adjustment might be required for other desktop configurations than the one with a 22px top panel and nothing else on the right edge.
2) A custom .desktop file: ~/.config/autostart/franz-startup.desktop
[Desktop Entry]
Type=Application
Version=1.0
Name=Franz
Comment=Franz Startup Script
Exec="~/.bin/Login-Franz"
Icon=franz
StartupNotify=false
Terminal=false
X-GNOME-Autostart-Delay=10
X-GNOME-Autostart-enabled=true
Note: You might need to change "~/" to "/home/YourUserName/" in the executable path.