Xcas may open different sessions, each with its own levels. You can move levels inside a session or copy a level from a session to another session.
You can move one level in the session, push the mouse on its level number and release it at the destination. If you want to move some contiguous levels, click on the first level, then shift-click on the last level (that is click on the mouse while pushing the shifT key). You can now move these levels by pushing the mouse in the selected area and release it at destination. You can also copy these levels in another session by Ctrl-C/Ctrl-V or select/middle click.
You can delete the selected levels. You can paste the selected levels elsewhere by clicking with the middle mouse button on another level number. You can merge the selected levels in a single level. You can also group the selected levels in a section and give it a section name, sections may be folded or unfolded.
File menu of a session will let you save/export/load/import
a session in/from the current session. The
from the top menu will let you insert a new session.