Keyboard not working in WebGL if loaded in background

Keyboard not working for me in WebGL builds if project loaded in background.

Project to test:
http://gasparfx.itch.io/webglkayboardbug?secret=x3vJHMCQencwS1JJeST7y3BIUi4

Code(I know its not good to add force in regular Update, but want to keep it simple):

Code (CSharp):

1. void Update () {
2.     if (Input.GetButtonDown("Fire1"))
3.     {
4.         cube.AddForce(Vector3.up * 5, ForceMode.Impulse);
5.     }
6. }

1. Open/Refresh page and minimize browser or change focus to some other application.
2. Wait till application loaded
3. Play game. I can push cube with mouse clicks, but not with Ctrl key.
4. If make game fullscreen Ctrl key works again.

Tested with Firefox and Chrome

 

I already did it, btw. Case 704225
But may be someone have a workaround for this? Some html editting f.e.

 

I think i found a better way to reproduce this.

http://prntscr.com/7hliur
After click on Zone 1 - Keyboard doesnt work in game
After click on Zone 2 - Keyboard works in game

Now in seems like an issue with html hierarchy on itch.io website.

But problem remains - focus is still lost after i click in game window with mouse. Its very unclear for users that they must click on empty space near the game.

May be now someone can suggest something to solve this?

 

BUMP!