How to edit Inkscape measure text for small measures?

Here's an example: open Inkscape 0.91, draw a line about 10+ pixels in lenght, and use the Extensions / Visualize Path / Measure Path ... :

Set the font to 5 px here; and note the text box of measure tool shows only "13", whereas the lenght (from the W box above) is 13.385 px.

If you say OK to this, and select the text box:

If you select it with normal pointer, it says below "Text on path [truncated]" (see also Inkscape - Dev - NEW: truncated text indication); if you switch to the text tool as on the image, you get a red outline, and if you open the XML editor, you can see that the full text is actually "13.38 px", but only "13" is shown, because the text is, well, truncated.

So my question is - how can I get this text box to show the entire text? It is namely NOT a frame, and there are not ANY properties in the XML that allow for the changing of the box size - so I cannot edit the size of this text box?!