I have problem with displaying Cam on QTLabel using openCV, Every thing is working fine . except one . I have to call function from open === cvNamedWindow() == in order for program to work properly . its displaying the webcam on the QLabel no problem but if i don't call the cvNamedWindow function then the program is just hanging its just keep displaying the camera which are working on the screen but i can't click on any thing else its getting freeze. doest any one has any idea why its happening and what i am doing wrong ?