Hi and welcome to devnet, Glad you found a solution and thanks for sharing ! One thing you can do is to take a look at the release logs to see what has changed. However from your description you may have found a regression. Did you already check the bug report system ?

@Hjortronsylt Well libraries are simply not interchangable. Each library does hold a couple of objects defining typically the functionality given in the general naming. Some namings may have changed between Qt4 and Qt5, but not network to anything. Also when your application is requiring network functionality, but is missing it in the link process, you should see somewhere error messages. I would suggest that it is best when you are checking out examples from the tutorials. There are the network examples and there is the testlib functionality however, Qt offers more different aspects and it may make sense for you to check out those as well.

@SGaist thank you, I took QFormLayout into account. @VRonin also thank you! I can not believe that it would take so much code to get this done... After starting over and over again I came up with this: GeneralTab::GeneralTab(QWidget *parent) :QWidget(parent) { QLineEdit *lineEdit = new QLineEdit("/dev/video0"); QGroupBox *groupBox = new QGroupBox("Settings",this); groupBox->setSizePolicy(QSizePolicy::Expanding,QSizePolicy::Expanding); QFormLayout *formLayout = new QFormLayout(groupBox); formLayout->addRow("Video Device: ",lineEdit); } and this looks exactly what I wanted, two widgets with a nice group box border sized to minimal space usage: https://pauledd.files.wordpress.com/2016/08/pat4.png I dont really know If this code is correct or might produce trouble but at least I dont find any errors at the moment.

thank you for the tip, I will try this in another project since I currently have a lot of problems getting qmediaplayer or qcamera working on the RaspberryPi. I wrote my code on amd64 on which everything worked fine but on the actual device (RPi) a LOT of problems came in (qt-gstreamer-v4l2-bcm2835-v4l2,MMAL, w.t.h.) but thats worth another thread.