[HELP] How to make main camera vieport work correct for UI Text

Hello! My project work fine, but I see big differrences between how I see borders around Text object in Unity Editor and how they look like then I start game (in Unity) or then I build & run my build as *.exe.

Here is an screeenshots. How borders look like in Editor (#Scene view) :

https://www.screencast.com/t/lLW0e3lJ9A9r
As we can see here Text object are very close to UI borders.

But it’s how they (borders aroud text) look like then I run game (from Editor or if it exe-build - no difference):

Screenshot

So how I can make borders between text starting point and application borders look identical for Scene view and in Game.

Thing I try: I try ro play with various Main camera settings and player setting for exe build but does not help.
Unity version: 5.6

It’s also look a bit strange why camera preview window ignore UI layer. Does it okey?

p.s. I apologize for not being word-perfect in English, please excuse any errors - it’s not my native language