Small bug with negations of traits

Per definition all things which are not explicitly “off” are “on”

@($Obj is on)   ~($Obj is off)

So the “switch” action leads not to the desired output “(The $Obj) can’t be switched on or off.”
unless you rewrite the following rule:

(instead of [switch $Obj])
    { ($Obj is on) (switchable $Obj) }
    (try [switch off $Obj])

Thank you! This will be fixed in the next version.