在browser界面，鼠标右键单击报错

[Jhering]

在browser 中的 fields cards 按钮旁边空白处，单击鼠标右键，如果没有装Fwq，会弹出 cut copy paste菜单，装了fwq以后，没有菜单弹出，并报错。卸载fwq以后，故障消失。再次重装，依然重现。win 10，anki 2.1

Debug info:
Anki 2.1.5 Python 3.6.1 Qt 5.9.2 PyQt 5.9
Platform: Windows 10
Flags: frz=True ao=True sv=1

Caught exception:
File "aqt\editor.py", line 982, in contextMenuEvent
File "anki\hooks.py", line 28, in runHook
File "C:\Users\liwen\AppData\Roaming\Anki2\addons21\1807206748\common.py", line 212, in on_setup_menus
each = maps[web_view.editor.currentField]
<class 'TypeError'>: list indices must be integers or slices, not NoneType