Feature: reattach a detached tab to hotkey window by dragging a window
It's possible to drag tabs between regular windows, but not to a hotkey window.
It's possible to accidentally detach a tab from hotkey window when rearranging tabs. It's possible to invoke hotkey window again when dragging the detached tab's window.
Requested feature: if iTerm window with a single tab is dragged, and a mouse is over hotkey window's tab bar, activate tab arrangement mode. If window is let go, attach its contents as a tab back to hotkey window.