uGUI: Raycasters sorting doesn't match Canvas sorting (4.6.1p5)

1. PROBLEM

When you have 2 Canvas with 'Screen Space - Overlay' render mode on same scene, set 'Sort Order' of one of the canvas to '-1' and leave the other as is ('0'). Now the canvas with sort order '-1' is visually displayed behind other canvas, but is the first one to receive clicks. Issue appears since version 4.6.1p2 of uGUI ( https://bitbucket.org/Unity-Technologies/ui/commits/7ac0f0d81f26c75250053db863a1b63bcf10c4bd?at=4.6 ) commit #7ac0f0d81f26c75250053db863a1b63bcf10c4bd , where EventSystem.RaycastComparer logic has been changed.

I assume that problem comes from the base value of sortOrderPriority and renderOrderPriority in BaseRaycaster. They should also be changed to int.MinValue (because lower value has higher priority).

1. REPRODUCTION

Launch provided sample project and click on highlighted area.