Fixed issue #1165 - Tabsets don't properly resize after removing one of them

I'm sorry I accidentally worked on top of my previous commit/bug about line height (and related merge with master, I'm still struggling with git at times), but I'd assume that commit is going to get merged either way eventually so it shouldn't be a problem (let me know if it is and I can try to work it out).

I fixed the issue as linked, I just added a function call to rebalance the tabset width after removing any tabset from the list.