I’ve updated ResizeAlign with a better face selection behavior that does not require you to move your camera around as much to get the faces you want selected – in particular allowing you to select backfaces without repositioning your camera.
The new selection behavior guesses your intent when clicking near the edges of parts, selecting the adjacent face instead if it thinks it would be more useful to select that one (if you still want exact selection you can change the Selection Behavior setting).
E.g., quickly resizing some road sections together:
In addition I also cleaned up the UI to have icons for clarity, better text rendering and tighter layout, and use modern UI elements (while keeping the classic styling).
EDIT: Another update, adde a rounded join mode:
Please let me know how you like the new behavior and if you run into any bugs (I made a non-trivial number of code changes in this changeset).