I have not found a way to place a non-visual component on the
component palette. If I derive from canvas or uicomponent it pulls
in unneeded overhead, but that is the only way it seems to have a
component show up in the custom components node in the component
palette. Is there a trick to force a descendant of Validator,
Manager or any non-visual base class onto the component palette so
properties can be set at design time?
Putting a non-visual component in the Components Panel is not
the real issue. Even if you could put a non-visual component in the
Components Panel (you can't), it wouldn't do you any good because
Design Mode only draws items that are visual components.
When you say you want to set the properties of a non-visual
component at design time, do you mean you'd like to set values in
the Property Inspector? A feature that we have considered for a
future version of Flex Builder is to enable the Property Inspector
to work in Code Mode and for non-visual items. You could select the
tag in the code view or in the Outline view and its properties
would be editable in the Property Inspector.
Or do you want to have some kind of iconic representation of
the non-visual item on the design surface that you could select and
manipulate? This is tricky from a user interface perspective.