when map/window lost focus, unable to select area

[fabripeco]

Hi,

first of all, thank you for this plugin!
Steps to reproduce:

• enable area selection and select area;
• change browser window or application;
• return back and select an area on the map.

It seems to be impossible to select an area again, until I disable and re-enable the area-selection. Only a small blue point appears where I clicked to start dragging. The same in demo version in website on my browser (Chrome 56).
Thank you!