How to set a graphics effect to a tree widget and its contents

[mrvk]

I would like to blur my mainwindow whenever a model dialog is shown on top of that. Using QGraphicsBlurEffect, I am able to set the background (mainwindow) to the desired effect. But if there is a tree widget in the main window, then the tree widget contents are not getting blurred.
How can I achieve that ?

Thanks for any help

[axeljaeger]

How do you set a blur-effect on the background of your MainWindow?

[mrvk]

I have created an object of QGraphicsBlurEffect and used it with 'setGraphicsEffect' method of QWidget. The main window has a dock widget and the dock widget has a tree widget with a few tree widget items. And the problem is that the tree widget items are not getting blurred.