I’m on Linux Mint 17, L.O. 188.8.131.52.
None of the buttons on the sheet tab bar for moving between sheets are working. They change appearance when clicked, as expected, but the sheet focus doesn’t change. I didn’t see a bug report for this.
What I really need is a keyboard shortcut for moving to the first sheet. I don’t see that option anywhere in the list of available actions in the Customize dialog.