PropertyHandle :: IsParent - Is property handle parent

The function checks, whether the current property handle is the parent for the property handle passed to the function. Especially for weak-typed or transient reference the function is able to detect, whether the passed property handle is still valid in the application context or not.

Sub-handles for weak-typed parents are automatically updated, when the parent's type changes.

When changing the property handle for a transient property handle, reopen events are generated but subordinated property handles are not updated. Moreover, sub property handles are still valid in the property handle hierarchy, but not in the application context. The function detects this type of inconsistency and allows the application to react.