Removing the button's href made a blocked window.open (popup blocker, null return) leave the viewer with neither the panel — the handler still hid it — nor a popout. When window.open returns null, send this tab to the popout route instead of hiding chat, and only collapse the panel when a window actually opened. 07-chat-popout covers the blocked path by stubbing window.open to return null: the tab must land on /chat-popout/<did> with no popup.