Parenting dialogs to child windows of top level windows is most likely
not defined behavior. It's also likely that this behavior varies across
platforms so it' best not to risk doing it. wxWidgets does not check if
the dialog parent is actually a top level window. There may be other
places we are doing this with our message dialogs so we should do an
audit.
ix the problem with the original template-based implementation to limit
the amount of things that could be forgotten by new panel creators
(since we can't just have a static fail method warning about things
beinf forgotten).
This reverts commit a92516bcd2.
On wxWidgets 3.0, SetSizeHints must be called once the panel is fully populated.
On wxWidgets 3.1.5, SetSizeHints is not mandatory but can be called to ensure
right sizes once the panel is fully populated.