found it

for the inner Pane I had to set

Pane { leftPadding: 0 rightPadding: 0

now all content from inner Pane is justified to content from outer Pane :)

found out that by default the Pane has a padding of 6

@jpnurmi thx forthe info. then I will remove this for mobile app development

icons depend on DevicePixelRatio and are named this way:

myIcon.png - corresponds to 1.0 and mdpi - use this name in qml
myIcon@2x.png - 2.0 and xhdpi
myIcon@3x.png - 3.0 and xxhdpi
myIcon@4x.png - 4.0 and xxxhdpi

if you want to know the DevicePixelRatio:

C++
qApp->primaryScreen()......

I've created a task https://bugreports.qt.io/browse/QTBUG-50984 so it doesn't get forgotten.

We will push only stabilizing bug fixes to the 5.6 branch, so it will stay compatible with the 5.6.0 RC/release packages. All new features are pushed to the dev/5.7 branch. Technically 5.7 is already feature frozen when the branch gets created, but modules previously stamped as tech previews have an exception so we can continue the development full speed. We still got plenty of things to do before we have earned the final stamp. :)