The column separation lines and Resize grips are not visible in Mac in Qt5 versions. It works well in Qt4. Since the column views are the default standard view in Mac(in Finder etc.,) it is important to provide native-look-and-feel to Mac users. Please prioritise this issue.

The minimal example to reproduce the issue is the simple tree model example from Qt Demos. Change the view as Columnview. See the screenshot attached and also refer the forum discussion