Cut a combined path along pair of non-connected nodes in Inkscape

I have a hollow closed path created by taking two closed paths and applying Path > Difference. I know the two paths are “identical”, but one is an inset of the other. (This could be done with one of the Path > Offset tools, but that ends up creating curves I don’t want, so I created this one by duplicating my closed path, giving the duplicate a wide stroke, Path > Stroke to Path, Path > Break Apart, delete outer path.)

Why changing font in Inkscape does not work?

I am trying to change the font of “x” in the figure below. I selected it with “Select” (the arrow icon) and then clicked on “Create and Edit Text” (the A icon) and I think the thin dashed line around x means that it is selected. Then I expected to be able to adjust its properties in the text toolbar on top, but to no avail. I changed the font to 10 size and nothing happened. I changed it “Perpetua” again nothing. Why? As far as I can deduce from the click menu the image is not grouped nor frozen.