It is sized for what looks to be 640x480 -- on a 1920x1080 screen.
The Settings/Display dialog offers options for only the client displays.
The only likely setting I've found is in the ~/.config/VirtualBox/VirtualBox.xml file :
Code: Select all
<ExtraDataItem name="GUI/LastWindowPosition" value="0,42,960,479,max"/>
It is interesting that 'Restoring' the window from Maximized before exit, removes the max value from the setting, so perhaps this setting is about the Manager window.
Deleting that file between invocations of VB has no effect.
There is a virtualbox file in /etc/default but there is no reference to display attributes in my version of that file.