Avoid selecting an element while zooming (pinch)

Hello everybody,
i am working now on a Project for railway industry,
On the program's main window you see a railway topology between different cities and you can zoom and pan in any direction you want with mouse or with touch events(Just like Google map),
There are also a lot of signals, railroads, and deflectors in my topology which can be choosen by user touch,
The Problem is when i try to zoom by pinch it sometimes chooses some element instead of zooming,
Any ideas to solve this Problem or does any of you know a good tutorial about advanced touch stuff?
Thank you
pardus