How to reproduce:
1. Create a new project
2. Create UI slider
3. In Hierarchy window select Canvas - > Slider -> Fill Area -> Fill (or Handle Slide Area -> Handle)
4. Move element with Move Tool
5. Press Ctrl + Z

Expected result: After ctrl + z pressed, (Handle, Fill Area or any other element of the slider) should move to the same place there it should be
Actual result: After ctrl + z pressed, part of the slider (Handle, Fill Area or any other element of the slider) disappears

Reproduced with: 5.5.4p3, 5.6.3p2, 2017.1.0p5, 2017.2.b9
Not Reproduced with: 2017.3.0a1, 2017.3.0a5

Note: Going into Play Mode fixes issue (elements appears)