Canvas: Ensure all element types are initialized before first usage.

Canvas: Ensure all element types are initialized before first usage.

If setting properties on a group a check is performed if
this property exists on any possible child element, and
only if this is the case the property is stored in the
groups style.

Previously elements have been only initialized during
their first usage, leading to ignored styles if they
have been set on a parent element before instantiating
an instance of the actual element type.