Issue in Safari 10.0.3

There seems to be a positioning issue in Safari 10.0.3 on macOS Sierra, i.e. the boxes are not placed correctly after reposition the boxes. (First move from bottom to matrix works well though)

Compare attached picture:

<img width="984" alt="screen shot 2017-03-30 at 19 19 31" src="https://cloud.githubusercontent.com/assets/9552031/24520025/9964db20-158f-11e7-89f3-c916d628c8bd.png">
