In the multi-pane, within the pane 1, I cannot use Tab, Shift+Tab, expand, collapse, or use + to create, tested in Chrome Incognito mode 4.3.2609081844 [beta, chrome-152, mac]. Cannot create a new pane using shortcut ctrl+r.
Other panes are normal.
Besides, tested in the 4.3.2609071723 [chrome-152, mac]
I have experienced significant lag/latency when creating a new bullet, expanding it, completing it, deleting it, and moving it between panels.