On Enlightenment 0.24.2 and xorg 1.20.10, when a window is iconified to the IBox, its WM_STATE remains as "Normal" rather than "Iconic". This causes some applications to treat the window as still being visible, such as Chromium - where dragging a tab between windows can get dragged into an iconified window unexpectedly. Other window managers such as Gnome shell set the _NET_WM_STATE(ATOM) window property to _NET_WM_STATE_HIDDEN as well setting this state to "Iconic".
I've noticed other window managers set windows on other virtual desktops to the "Iconic" state also, which prevents Chromium from incorrectly placing dragged tabs into those unseen windows. This is also a problem in Enlightenment 0.24.2, where those windows on other desktops are left in a Normal state and can have tabs unexpectedly dragged into them even though they are not visible to the user.