resizing widgets when user resizes mainwindow

[Mystical Groovy]

EDITED

ive tried to lay my widget under a grid layout, for some strage reason the app compiled and run ok but i lost connection with my .cpp file, for ex i clicked on a button on my app and nothing happened! lol, when i removed the grid layout everything worked correctly again :P..

ive also tried to right click to my tabwidget and lay out as grid layout, but then i couldnt setup the widgets where i want them to be in the form.. lol...

so lets forget the layout method, i dont have a problem to code all of my widgets in the app to resize automatically as long as i know how to do it...

so please help hehe xD