Dialog widget doesn't have a layout initialized

[vladwing]

There is an exception when trying to use a Dialog widget in ENAML. The problem seems to be self.layout() in QWindowBase.setCentralWidget() returns None.

While digging deeper, I discovered the problem in QWindowDialog inheriting from QDialog and QWindowBase. Somehow QWindowBase.__init__ doesn't get called by QWindowDialog.__init__'s super call.

Example code Using latest Enaml with PySide, on Linux

[sccolbert]

Duplicate of #108

[MatthieuDartiailh]

Work on supporting for PySide2/6 have fixed this issue.