i found in OS that you can activate touchscreen test:
1- go in preferences
2-go down to "About"
3-go down to general informations
4-select it many times until you have "dev lab activate "
5-now you shoud have a new menu "Laboratory" at the botom
6-go down to pointer position and activate it
7- now on touchsreen, if it works, you should see a little square at the place where you're pressing and multipoint while scrolling.
1- go in preferences
2-go down to "About"
3-go down to general informations
4-select it many times until you have "dev lab activate "
5-now you shoud have a new menu "Laboratory" at the botom
6-go down to pointer position and activate it
7- now on touchsreen, if it works, you should see a little square at the place where you're pressing and multipoint while scrolling.