fix the awk expression in currentWindowId().

[igwan]

On my system currentWindowId always return "_NET_WM_NAME," due to another occurrence of "NET_ACTIVE_WINDOW" in xprop -root result :

_NET_SUPPORTED(ATOM) = _NET_SUPPORTING_WM_CHECK, _NET_WM_NAME, _NET_WM_STATE_HIDDEN, _NET_NUMBER_OF_DESKTOPS, _NET_CLIENT_LIST, _NET_CLIENT_LIST_STACKING, _NET_CURRENT_DESKTOP, _NET_DESKTOP_NAMES, _NET_ACTIVE_WINDOW, _NET_WM_DESKTOP, _NET_WM_STRUT

[Menschenkindlein]

:+1: I have the same problem.