Risky?

The only precedent I can think of is when Apple introduced MacOS X and did a similar move of the buttons from right to left. However, that was an entirely new operating system with a completely different look and feel, which is very different to an Ubuntu upgrade.

Moving the buttons around does seem pointless, and I strongly suspect it was not properly tested for usability - that would at least have caught the tendency to click one of these buttons when trying to click the Edit menu.