Post #478: 
draguu:
Hey raoaoa , everything is working fine , just wanted to ask you one thing , is it possible to work on viewport ,while popup menu is open ,
like it wont close untill we press OK button , is it possible ? ,
right now when we click on viewport popup is going off
Unfortunately, it’s impossible in Blender 2.7.
But Blender 2.8 will have lots of UI changes. Who knows, maybe the devs will add this feature.