SwallowRetainSize - bakkeby/dusk GitHub Wiki
If a child window swallows a terminal then by default it will inherit the terminal's size and position.
Likewise the terminal window will inherit the size and position of the child window when it is being unswallowed.
If desirable then the size of the terminal window and the size of the new window can be
completely independent of each other by ensuring that either of the two have the
SwallowRetainSize flag set via client rules. This will allow both windows to
retain their original size when being swallowed / unswallowed.