The purpose will be more apparent after you have scraped a few new movies,
I added it for myself more than anything else, I have a lot of Jackie Chan movies, and when they are first scraped the title is often meaningless to my strictly English thinking.
The drop down box allows you to select from alternative titles available on IMDB, these alternative titles are added to the nfo and can be switched between.
Most people will not use this feature much, but those with large foreign collections will no doubt appreciate it.
Otherwise, it should function in an identical manor as the previous textbox.
Being highlighted on startup should make no difference to the function.