With the multiple changes to "Cover of Darkness", from having only a commandline parameter that affected the running instance, to only having a menu item, to now having command line parameters that don't affect the running instance, the documentation shows signs of this:
-darkon -darkoff These options will turn on and off the dark mode setting for the main
screen (‘Cover of Darkness’). Note that these only affect the launched instance.
(bold emphasis mine)Other entries in the "Command Line Options" section use the phrase "This does not affect the instance that is already running.", or some variation of it; Having this one be the exception is somewhat confusing (despite otherwise being accurate).
If you right-click on the VoiceAttack icon in the top-left corner of the main screen, you’ll see an
option for, ‘Cover of Darkness’. Checking this option this puts the main screen in, ‘dark
mode’, which might be useful when using VoiceAttack at night. To go back, just click on the
menu item again (note that this used to be a command line parameter, but that parameter has
been removed).
(bold emphasis mine)EDIT: Changed with v1.8.5.6