How i can search all my lists for a specific film title?

@motionpiclover To do this, visit the title page of the title you want to check; click the down arrow to the right of the yellow watchlist button on the right hand side opposite the poster.  This will show you a menu of all of your title lists; any lists which contain this title will have a green check to the left of the list name (otherwise there is a “+” in this spot). 

Hope this this helps.