Comment 10 for bug 1362534

Another thing I noticed: If I group the objects before calling the extension and afterwards ungrouping them I get constant stroke widths (if the preferences allow for optimized transformations). Unfortunately I didn't find any code that easily groups objects and also ungroups again while doing the aforementioned transformation optimization. I don't know if that would be a viable option it might at least give a clue how to make stroke widths as expected.