Steps to reproduce:
1. Download and open attached project "GUI_Toolbar.zip"
2. Make sure Inspector window is small enough to have scroll bar (detach it if needed)
3. Open scene "TestScene"
4. Select object "Test" from the hierarchy
5. Scroll the inspector down

Actual result: Custom GUI.Toolbar is moving at different speed than other elements (see attached gif)
Expected result: Everything moves in uniform

Note: Everything works fine if line 20 is "#if true" instead of "#if false"

Tested and reproduced on:
Windows 10
Unity 5.1.4f1, 5.2.4p1, 5.3.4p2, 5.4.0b14