Prevent clicks while scene is loading.

So I've got a strange problem here. When I press button to load level 3 (for example) I can mouse click when loading. Then scene is loaded my clicks are playing like whey were remembered during loading time.

P.S. i've tried to make bool variable that becomes true OnSceneWasLoaded() but still clicks are firing.

P.P.S. Same thing when game is loading on a device. I can click on my menus while still Unity logo on screen. (actually not the same but maybe someone will answer too)