Describe the bug
A bit of a tough one to explain:
When you have a Popout window that's a single panel, and drag that panel back into the dock, it will order itself incorrectly among its neighbors.
This doesn't happen when you drag the whole popped-out group, only the popped-out panel.
This only happens if the position you drag it to is a neighbor following the position from where it was popped-out.
If this happens at the far edge of a set of neighbors, an IndexOutOfBounds occurs, and the panel is lost.

To Reproduce
dockview.dev provides a number of examples with Code Sandbox templates. Are you able to produce the bug by forking one of those templates? Sharing a link to the forked sandbox with the bug would be extremely helpful.

Best demonstrated by video:

Desktop (please complete the following information):

• Chrome
• Dockview v latest (4.7.1)

Additional context
This issue becomes very apparent and problematic when trying to do regular popout panel operations with singleTabMode=fullwidth