Chameleon can be used only to change the colour of objects. It cannot be
used to create new objects or give fill colours to non-existent objects.

Load the file "No_fill" into Chameleon. The colour of the hexagon on the
right can be changed but it is impossible to change the colour of the
hexagon on the left because it is not an object.

If you load the file into Vector or Draw you will see that the hexagon
is, in fact, six separate lines arranged to form a hexagon. As such, it
cannot have a fill colour. If you ever have problems giving colours to
non-coloured objects in Draw files it is highly probable that the objects
are not objects which can have a fill colour.