Inkscape halts after editing text (typically newlines, but not only) on Debian jessie

This problem was really driving me crazy: Inkscape was halting -- somehow unpredictably -- often after editing text (typically newlines, but not only).

I looked on the internet, but I haven't found a lot, beside an advice to put the language support to "None" in the preferences. It did not work.

However, at a certain moment I start receiveing a few dialog windows asking for installing python-uniconvertor, as it was necessary for inkscape.

I discovered that this package exists in Debian wheezy, in stretch, but not in jessie.

I installed the version from the stretch distribution: 
https://packages.debian.org/search?keywords=python-uniconvertor

and now everything seems to work!