_NET_SUPPORTED

The whole specification cannot be fully implemented in an external tool, for multiple reasons (need to redirect root window events, keep track of window states, …).

Only the following atoms are supported by ewmh:

• _NET_SUPPORTED
• _NET_SUPPORTING_WM_CHECK
• _NET_WM_STATE
• _NET_WM_STATE_FULLSCREEN
• _NET_CLIENT_LIST
• _NET_CLIENT_LIST_STACKING
• _NET_ACTIVE_WINDOW
• _NET_WM_WINDOW_TYPE (all types)

_NET_SUPPORTING_WM_CHECK

The specification require that a running window manager creates a window and point the hint to this window. ewmh will set the override_redirect property on this window so that non-EWMH compliant window manager will ignore it as well.

_NET_WM_STATE

The only supported state in _NET_WM_STATE_FULLSCREEN. When such event is sent to the root window, ewmh will respond to the event accordingly. When setting a window fullscreen, its current position, size and border width are saved in an atom named ORIGINAL_SIZE. ewmh needs this atom to revert the window back to its original state.

_NET_CLIENT_LIST

_NET_CLIENT_LIST_STACKING

These atoms hold the list of windows that are managed by the window manager (override_redirect unset), and/or have the hint _NET_WM_WINDOW_TYPE set to one of those values

• _NET_WM_WINDOW_TYPE_UTILITY
• _NET_WM_WINDOW_TYPE_DIALOG
• _NET_WM_WINDOW_TYPE_NORMAL

Because we don't know the order in which the running window manager is storing the windows, _NET_CLIENT_LIST also displays the window IDs in their stacking order.

All other windows will have their override_redirect attribute forcely set to 1, so that window managers without support for EWMH atoms can ignore them.

_NET_ACTIVE_WINDOW

This hint is updated whenever an event of type FOCUS_IN is generated. This should usually match the currently active window from the window manager point of view.