iTunes' Playlists

[Wrangler3]

I'm sure there's a way you can tick and untick all songs in a playlist with just one or two keystrokes but I'm blowed if I can remember how or find out how to do it! I unticked all songs in oneplaylist and now need to retick them but balk at the idea of doing it one by one by one etc etc. Anyone know how?

[fever28]

I'm on a train so can't check, but. Ctrl + a. Normally selects all