Everything is correct. I have reinstalled and these three buttons are
done by as you already stated. Thanks! It was two reasons.
THANKS!!!

I meet the same issue today. So i download the older version of Qt.

solved it by doing:

sudo apt-get install mesa-common-dev

and by removing and copying over src/gui dir

@Henrinacio so you don't have the correct version of Visual Studio installed. You installed Qt for Visual Studio 2012 and 2013. On Windows you can't just mix and match like that. The different version of Visual Studio are not compatible one with the other. So you have two solutions:

Install VS2013 to use Qt for MSVC2013 Build Qt yourself with VS2015

Just did mark it as solved.
This might be because you have signed up lately. Not sure what the restrictions are, but it is meant for spam prevention.

Otherwise at your top post respectively any other post you should see a gear wheel at the right. Click on this and on the left button showing up. In general it is self-explanatory and I am sure you will find it next time.