When I click to select a single track segment, then I get its length printed in the status on the bottom of the window. But if I select multiple connected track segments (say via right-click/Select/Trivial Connection), the status does not display length anymore, having turned into this:
Well, here is something: I watched Kicad - Differential pair routing and trace length matching - YouTube - and if I understand it properly, one can use Route/Tune Track Length (having been set to Route/Single Track mode) tool - once it’s selected, the cursor turns into a crosshair, and you can click the track:
When you click on the track, you get a status text displayed, here “Too short: 32.476 mm/100.00 mm”; the first number (here 32.476) is the selected trace actual length (it will be indicated in yellow), the second number (here 100) is the target/desired length (see the video on how to set the target up)
So, this is great for measuring a complete track, but I cannot see yet if this can measure a selection of traces which is a subset of the entire track, say, as on this screenshot?:
