Edit/delete only last segment of trace

It is fairly easy to accomplish this. When routing check that the following are checked in the find filter before you route, "Cline" & "Cline Segs"

Route in your trace. When your finished hover the cursor over the trace and use the tab key to cycle between the whole trace and just a segment of the trace. When you press the tab key you should see the whole trace highlighting or just the segment of that trace. In the case of a segment just right click delete to remove it.

i'm using pcb editor 17.2-2016.  no matter what i do i cannot delete a trace.  when i click on it sometimes it changes to blue or red stripes.  when i right click i don't have a delete option. pressing the delete key or clicking the red x doesn't work either.  this program is the opposite of intuitive.  any suggestions

i'm using pcb editor 17.2-2016.  no matter what i do i cannot delete a trace.  when i click on it sometimes it changes to blue or red stripes.  when i right click i don't have a delete option. pressing the delete key or clicking the red x doesn't work either.  this program is the opposite of intuitive.  any suggestions

Click delete first, then make sure you have either CLines (whole trace) or Cline Seg (trace segment) selected in the Find Filter. Then click n the trace. 

Something else to check is right click over the trace and from the drop down menu, disable Single Click execution under Customize.

I always disable this because it is annoying and limits options in my opinion. Yes, the Delete key on the keyboard is useless.

Umm...  Allegro, out of the box, the delete key is useless until you alias it to the delete command. 

This makes me happy, BTW.   Saves replacing/recovering what CAD tourists decide to delete during review.

Try selecting an object, then Ctrl-D.  It's brilliant because it's an easier keystroke without moving my hand as much.