The active window was used by the NLA and the Graph editor however this is not always available and not necessarily the window that contains the area being initialized. Potentially causing the graph and NLA spaces to be initialized with the wrong scene. Active window access caused various awkward fixes in the past ([0], [1], [2]) which worked around the active window not being set. Use a lookup for the window instead of accessing the active window. Note that passing the window is an option too however this is only used for versioning older files and is not be needed in most cases. [0]:20788e1747[1]:42f6aada98[2]:480e467ac9