Lists: Detect duplicate entries in same list

A single movie gets added TWICE if you are on the movie page and add it to the list ONCE.

Please fix. It's annoying!

See discussion here as to why people might want to add duplicate films to a list:

https://getsatisfaction.com/imdb/topi...

An alert would be the ideal compromise.

This reply was created from a merged topic originally titled Preventing the same item being allowed more than once on a list.

i don't think that a character, person, title etc... should be able to be listed more than once. perhaps giving a message that it is already on your list if you've by chance forgotten. as an example i think GiantBomb does a good job at it.

This reply was created from a merged topic originally titled An addition to the LIST function.

Would it be possible to add the function of checking a list for prior additions to keep from getting multiple lists of the same film.  Maybe have a "FILM ALREADY IN LIST" flag pop-up before the adding goes in.  It would REALLY be a help in trying to build good lists.
Thank you

I found a hacky way to batch remove duplicates from a list I'll call "my list". Because the watchlist does not allow duplicates, you can do it like this:
1. Move your watchlist to a list "watchlist backup"
2. Move "my list" into the watchlist
3. Move the watchlist back into "my list"
4. Move "watchlist backup" back into the watchlist.