#398 Speed up adding of songs to the set please

[petrusek]

Song lookup modal dialog (Set Mode / New Item / Song) seems to be quite slow to load & show (probably depending on amount of songs in database). Once you find your song and click Add button, dialog disappears, main window freezes for quite long while, redraws with updated set and then it takes some additional time to show dialog again... I believe that this sequence includes some unnecessary operations and could be shortened which would significantly improve user experience.

I am quite often in situation when I need to build set of songs as quickly as possible, but this is holding me back and training my patience ;)

I have no idea how it is implemented but from described behavior it looks like new instance of Lookup dialog is being created and re-populated for each single song. If existing instance of dialog would not disappear and could be reused for next song while main window in backround was refreshed asynchrounously, it would be great. Besides sending current song to main window the Add button could just clear "Quick Lookup" and "Custom presentation order" textfields and that would be it. Maybe I am mistaken and there is some other expensive operation taking that long, but anyway - having this faster would make me (and I believe even other users) happier.