Re TEST and Re Edit (2022):
Difficulty to install it on a new Quantum, but finally re work...
:-)
I Re ask same requests:
- Can you add to the Dev menu and the Normal Context menu:
"Open With Chropath"
- Give to the selector Dashed Color line an Z-index which make it always visible .

- Selector Menu:
> Remember the last Choice used (Abs Xpath, Rels Xpath or CSS) .
> Change the color background of this menu (It's black and its items too, so they are only visible on hover them).

- Result Code panel:
> Style it like the normal HTML panel code Dev Tools by using Color Highlighting
> Add a menu to an selected HTML item in it: "See it in the HTML panel"

Old Review (3 years ago):

Thanks, that's the better alternative to my beloved "Firepath" ( that i use a lot to manipulate CSS with ..... Waterfox).
PS:
It's possible to use Chropath on AMO page by going in about:config (tested on Firefox Quantum):
How to enable Firefox WebExtensions on Mozilla websites
[https://www.ghacks.net/2017/10/27/how-to-enable-firefox-webextensions-on-mozilla-websites/]


Suggest ( to be more closer of Firepath simplicity) :
1 - Add to the Chropath panel a HTML box (as it is in it in the right panel of the in-build inspector tab) under its matched results to:
- Highlight all matching results by Chropath.
- Click a matched result to go directly at the right position in this Chropath HTLM box
2 - Add a way to chose a match and go directly to the original inspector panel
3 - Add the inverse function :
Choose an element in the original inspector right HTML panel and send the request to the Chropah tab
4 - Add an option to only display Xpath ot CSS selector (for my use Xpath selectors is not important)