sub window shrinks on Linux when opened through main window.

[Ratzz]

I have a main window. I open sub window through the main window(menu->new window) .The sub-window is a vertical layout which consists of stacked widget, sidebar-frame . In windows , if i open sub-window through main window it opens properly (with all items at proper position). In Linux ,if I open sub-window through main window it does not open as it opens in windows. In Linux all the items,push-button, label shrinks when new sub window is opened . If i click the sub-window once using mouse it appears properly without shrink. How to make a sub-window click while opening it ?
Or is there any other way to do so ?
Before clicking . After click it looks like these.

[SGaist]

Hi,

How are you building your sub window ?

[Ratzz]

@SGaist
Through the designer.

[SGaist]

Did you put all the widgets in layouts ?

[Ratzz]

@SGaist
The led you see in the image is the Qled . which is the promoted toolbutton .
Yes i have toolbutton,labels, lineedit etc in my QVBoxLayout .

[Ratzz]

I did use resize()to re-size my sub-window .

[SGaist]

When are you doing it ?

[Ratzz]

@SGaist
while opening the subwindow.

[SGaist]

In the constructor or in the showEvent ?