about qt/embedded widgets showing in ARM platform

Hi:
guies.I am a rookie to this forum, I have encounterred some problems about
qt/embedded widgets showing in ARM platform, the situation as follows:
I have compiled a program that with some QWidget objects in a QwidgetStack object to use QWidgetStack to switch the showing widgets,what is more,some of these widgets in widgetStack have many sub control(ie:there is a widget contains 30 pushbuttons ).when i running this program, no error encountered, what dispointting is that whten switching the
showing widget, if a widget with a lot of sub controls is showed, the subcontrols in it will
showed with a fast and slow sequence(some sub controls showed fastly, but some sub controls showed slowly), but they are not showing together at the same time,this process of showing will give user an inpleasent experience.
I think the limit of the hardware i used is some part of the reasons(ie :the lcd for the
embedded develop board certaintly could not catch the lcd for pc )for the problem, but
to improve the level of the hardware i used is not a thing with much possibility.
I want to find a approach that when showing the hidden wiget with a lot of sub controls,
don't make it to be visible before all of the sub controls are showed to make the displaying
of the wiget switching have a flatter user experience.
but i don't have any entrance to solving this problem, if anyother that have encountered problem like this may give me some help, thanks a lot.