Bug (v9.4) Workspace sometimes incorrectly restores tab groups

[IanOfYork]

When a workspace has documents split into panes (tab groups), saving and later reloading the workspace will sometimes restore panes split vertically as panes split horizontally.

This does not happen often and the pattern behind this is not at all clear.

[IanOfYork]

This may not be the same bug, but restoring a workspace that had 4 tab groups will often restore with only 3 groups. Likewise 3 will often restore with 2. The group widths are generally lost as well.