On my Ubuntu 12.04 32 I had to make *.sh files executable to make it work - which is obvious but perhaps not to all.
Undo function function doesn't know anything about plugins (ditto) - but you don't have to save (save before

).
toc.ncx shows the old data (uuid) - you have to save and open again to see changes - which only shows that I don't know my Sigil yet

.
And when speaking about not knowing: at the moment Sigil monitors the tmp files and reacts immediately to any changes - is it reliable feature?
Nice.