Gray Out Parameters of an Operator in the F6 Menu

I’m trying to get my ARewO to be a GUI addon.
I’m getting good progress, but 2 questions remain:

  1. If no Armature is selected, I’d like to gray out (removed, but preferably grayed out) the checkbox for “use armature” in the F6 or T-menu

  2. (more for convenience) I hope this is possible
    I’d like to create an object select list to select the object for the world location of the duplicates - also in the menu after you pressed run

in the draw() method of your panel or operator, you can do e.g.:

col = layout.column()
col.enabled = 'ARMATURE' in (ob.type for ob in context.selected_objects)

# if property is declared as bpy.types.Scee.the_prop = bpy.props.*()
col.prop(context.scene, "the_prop")

# if it's an operator property
col.prop(self, "the_prop")

There’s also an .active property for layout elements (layout, column, row, …), which will gray the property out, but still allow for user input in that mode.

Sorry for the late reply, a lot of the times Blenderartists doesn’t complete my posts