Touch Screens
When using touch screens you need to set the size of buttons and tabs larger than normal.
Tabs
To set the size of tabs in a Tab Widget use the tabWidget styleSheet.
QTabBar::tab { height: 50px; width: 100px; }
will set the size of the tabs
larger and easier to press with your finger.
And you can see the tabs are large enough to touch with your finger on a touch screen.