hide/show screen update problem

[SkripT]

Hi, In a main window I have an image and an information window beside the image all in a HBoxlayout . I want to make an option in my program that let the user hide/show the information screen. So if the information is hidden, the image has more space to be shown. The problem is that if I call to show or hide functions of the information screen and after I want to know the new size of the window that contains the image, its size has not been updated yet. I want to know when the layout is updated after calling show or hide of one of its widgets. I have tried calling repaint or update of the main window but no results. Thanks.