I noticed a little thing that could improve readability of the progress bars used to display "Link quality" "Signal level" and "Noise level".
Values in the progress bars are actually always displayed with the same text color. Since the bar color seems to be the same as the selected text background color, it could be easier to read if the text color change to selected text color when the values are displayed over the bar.
i.e. When "Link quality" is weak (below 40%), the bar is short and the text appears in the bar background. The value could be display with normal text color.
When the "Link Quality" is good (above 60%), the bar is longer and the text appears over the bar. The value could be displayed with the selected text color.
I noticed that too, it depends on the theme I think. I'll browse the Gtk+ documentation to see if it's possible to change these colors.
Edit Found nothing in the doc