GUI elements get clipped when zooming out of the canvas by modifying the GUI.matrix. In previous versions of Unity it had no problem displaying the elements. For example, if a texture is drawn using GUI.DrawTexture with the rect value of (x:550, y:300, width:76, height:90) it'll get clipped even though the size of the canvas is (x:0.00, y:50.00, width:800.00, height:800.00).

Steps to reproduce:
1. Open User's attached project
2. In Menu bar: Tools > Window Test
3. In the appeared window Change zoom level from 1 to 0.75

Result: Texture gets cut / cropped.

Reproduced with: 2017.1.0b2
Not reproduced with: 5.6.0p3