Crash on Linux "AttributeError: 'NoneType' object has no attribute 'value'"

[MadMartian]

MCEdit Unified bug report template. For MCEdit 2.0 bugs see here : https://github.com/mcedit/mcedit2

Description of Issue:

MCEdit fails to start, classic NPE (Null-pointer exception): "AttributeError: 'NoneType' object has no attribute 'value'"

MCEdit Version:

v1.6.0.0

Minecraft Version the world was last opened in:

A 1.7.10 custom modded world

Operating System:

Linux 5.4.0-90-generic #101-Ubuntu SMP Fri Oct 15 20:00:55 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

A screenshot or full text of the error from the console:

[ ERROR][ root.py:1013]:MCEdit version Unified v1.6.0.0 %s Minecraft 1.8-1.12.2 | PE 1.6
Traceback (most recent call last):
File "mcedit.py", line 1076, in
main(sys.argv)
File "mcedit.py", line 1010, in main
MCEdit.main()
File "mcedit.py", line 856, in main
["Don't remind me again.", "OK"], default=1, cancel=1)
File "/opt/oss/MCEdit-Unified/albow/dialogs.py", line 178, in ask
return box.present()
File "/opt/oss/MCEdit-Unified/albow/widget.py", line 538, in present
self.root.run_modal(self)
File "/opt/oss/MCEdit-Unified/albow/root.py", line 361, in run_modal
self.size = (event.w, event.h)
File "/opt/oss/MCEdit-Unified/albow/widget.py", line 48, in set
self._resized(old_size)
File "/opt/oss/MCEdit-Unified/albow/widget.py", line 182, in _resized
self.resized(dw, dh)
File "/opt/oss/MCEdit-Unified/albow/widget.py", line 188, in resized
widget.parent_resized(dw, dh)
File "/opt/oss/MCEdit-Unified/albow/widget.py", line 233, in parent_resized
self.rect = Rect((left, top, width, height))
File "/opt/oss/MCEdit-Unified/albow/widget.py", line 163, in set_rect
self._resized(old_size)
File "/opt/oss/MCEdit-Unified/albow/widget.py", line 182, in _resized
self.resized(dw, dh)
File "mcedit.py", line 663, in resized
maximized = win.get_state() == mcplatform.MAXIMIZED
File "/opt/oss/MCEdit-Unified/mcplatform.py", line 997, in get_state
if state.value:
AttributeError: 'NoneType' object has no attribute 'value'

How to reproduce:

Consistently reproducible, MCEdit refuses to start

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Adding the following lines to mcplatform.py on line 995 resolves the issue:

	if state is None:
		return NORMAL

It appears the _NET_WM_STATE property is absent, this code I've manually added is a workaround, and then I was able to load a world, copy chunks, then paste them into another world, save.