This problem has been bugging me for a long long time and everytime I find a working solution and moves on but after some time , the same problem again crops up in another dialog and once again I look for some other solution
This is regarding the resizing of the dialog boxes according to the content of the widgets inside it. I got the solution on the same forum i.e use
Qt Code: 
  1. setSizeConstraint(QLayout::SetFixedSize)
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but this was not liked by people as this solution does not allow then the user to resize the dialog box manually.
Then I came to a conclusion that the widgets has to be on the main layout and you have to apply some layout to a dialog box and then only the widgets on the dialog will resize

Another time a dialog box with a frame which was having the same problem, now agian back to finding the solution, this time I observed that in the existing file, the minimum size of the Frame was set to some value and as I remove the value and put the minimum size to (0,0) it was working as expected. And offcourse every frame and the dialog box need to have a layout.
Now this is beyond my understanding that how come minimum size can restrict the frame from resizing. So can anyone please help in explaining this weird behaviour otherwise I know that once again another dialog box might come with a different kind of problem for resiziing.
Thanks for reading such a long query :-)