Currently, when adjusting the ToC using the "Insert Index or Table of contents" window, these changes are not recorded for the 'undo' history. If there are items in the undo history, these are even erased! (after changing the ToC, the history list is empty and undo button is greyed-out)

This is very annoying if you make adjustments that don't work out as expected, but cannot easily change back to previous state.

E.g. when trying to adjust tab stop distances, you may accidentally end up with a very ugly ToC (the page number being on the next line). You'd have to know which the tab stop position was previously.

Ubuntu 14.04
Version: 5.1.1.2
Build ID: 1:5.1.1~rc2-0ubuntu1~trusty0
CPU Threads: 4; OS Version: Linux 3.13; UI Render: default; 
Locale: en-GB (en_GB.UTF-8)