iOS Simulator 10 does not refresh

I try to simulate a very very simple application which I have created in Xcode 9.2. I try to simulate it in the iOS Simulator in an iPhone6 with iOS 11.2. I have also tested other devices with the same result.

On a real device, the app works as expected. But on the simulator it doesn't.

I expect, that the button will become orange after I have clicked on it. and the emoji should disappear. Instead it changes into some strange "shadowed" look. If I wait then, the button will sometimes turn its background to orange after around 30 seconds.

The button gets also drawed correctly instantly, if i force the screen to update with a button press, or with draging down the info center.


I have recorded a gif, to illustrate the problem.


http://www.giphy.com/gifs/l4pSUuBtN7aBVvbVe


Here is another GIF: http://www.giphy.com/gifs/26DNe5B0vxIO6pHiw

The button gets refreshed, as soon as i drag down the info center.


Development machine: Mac mini 2011, i5, SSD, 8GB RAM, high Sierra


hope someone can help me.