I just tried to alter the downloaded version of this drawing, but some objects, most notably the lines connecting annotations to their associated objects, can be selected, but not altered with the node tool - why is that? Addittionally, in the XML Editor the image looks quite weird

Can anybody comment?

Select uneditable line end click "Path -> Object to path" to make it editable with node tool.

loonquawl wrote:the lines connecting annotations to their associated objects, can be selected, but not altered with the node tool - why is that?

No idea, but if you take a look at a file header (not visible in built-in xml editor), you will see that this file was not generated by inkscape:

yes - that did it. Thanks a lot. the lines are called "svg:line" and ( if they have more than one node) "svg:polyline" in the XML editor, and i always assumed the (straight) output from Freehand and Bezier would also become thus, but they all simply become a path...

loonquawl wrote:Addittionally, in the XML Editor the image looks quite weird

I've noticed that with many non-Inkscape SVG files. It appears to be caused by the xml:space="preserve" on the root element.