While debugging libTERE this strange one turned up. Basically what happens is that dump2.svg shows 2 lines a certain way,
and dump3.svg adds a third line. The addition of the third line somehow changes the rendering of the 2nd line, even though
in dump3.svg the relevant xml for line 2 is unchanged. All tested versions of Inkscape do this.
A bit more detail. The two dump files draw first a rectangle around the paragraph, then a rectangle where each line will be,
then each line of text (in red), and finally, the entire paragraph (in a <text> structure) is drawn in black. When everything works correctly the black text exactly overlays the red text. That is what happens in dump2.svg. However, adding a third line causes,
for some obscure reason, the 2nd red line to be drawn in the wrong position. If you diff dump2.svg and dump3.svg the XML
for that draw is unchanged.
Files that will be attached:
dump2.svg the two line variant
dump3.svg the three line variant, dump2.svg plus one more line
dump2vs3.png screen shot of the two displayed, demonstrating the offset of the second line (red text, line rectangle)
caused by the addition of the third line.
Oops, let me correct that. The red text did not shift, what shifted was the overlaying black text for the second line. (I should have put a ruler on the screen earlier.) So the change that matters is the addition of the <tspan> for the 3rd line after the
(unchanged) <tspan> for the second line.