navigate_to_prev_item (navigate to previous sibling; shortcut: meta+shift+9) works normally in the new pane, but navigate_to_next_item (navigate to next sibling; shortcut: meta+shift+0) does not work in the new pane (Only effective on the leftmost pane).
Besides,
the next item (sibling) command, when invoked in pane 2 or later, affects pane 1.
Still present in 4.3.2609122032 [beta, edge, win]
Also, unsurprisingly, navigate_to_prev_item has the same issue (affects pane 1 no matter which pane it is invoked from.)