bindings only work correctly on ported properties

When using properties in a binding, that binding only works correctly if the properties used are ported to the new property system. Unported, old-style properties do not trigger re-computation when they change.

Thus, in order to formulate a correct binding, the author of the binding has to go into qt source code and check whether the properties she uses are already ported.

Do I get this right?

Source code for illustration attached.