PR# 19536 Enhance navigation setting previous location when right-clicked and dropped

When picked and dropped for a feature or a variable, the previous context is not saved, and should be to be able to navigate with `back` to previous location

Reproduce: 
1) go into a class into editor, scroll to a certain location, pick and drop in the same class a method
2) click back button <- to go to previous location, you'll finish anywhere and will loose your context (which is really annoying and disconcerting)

Solve (I think):
on_drop -> 
    set old location for back function to picked location
    do the stuff you already are doing which is setting the location to the beginning of the picked method or variable

Reproduce (same as description): 
1) go into a class into editor, scroll to a certain location, pick and drop in the same class a method
2) click back button <- to go to previous location, you'll finish anywhere and will loose your context (which is really annoying and disconcerting)