If you were ok with the replacement happening *right now* then the default double click behavior would work for you. It's "replace playing now (all)". But you want *next* to play. I can think of a couple of ways to do it depending on your exact requirements. Let's start easy and get harder as we go.
Method 1:
1. Right click on the playlist name. Select More Play Options > Add (as next to play)
This will get you what you want, but it will *insert* the new playlist, leaving the remainder of the original play list at the bottom. Also, this plays the playlist from the very beginning, which you may or may not want.
Method 2:
We're going to play your second playlist from a certain spot down to the bottom. So for example in a list of 50 songs, you might choose song #10 and want to hear 10 through 50.
1. Open the play list and find the first song from it you want to hear.
2. Single click that song.
3. Scroll to the bottom of the play list.
4. Hold Shift and left click the last song. This selects all the songs starting with the one you chose at the beginning.
5. Right click. More Play Options > Add (as next to play)
This still inserts these songs in place, with the rest of the old playlist still at the bottom of playing now. But you get to start the second playlist from the spot you want.
Method 3:
Now we'll do a full replace so that none of the original playlist hangs around, other than the currently playing song.
1. Go to playing now and single click on the currently playing song.
2. Edit > Invert selection. This selects all the songs in Playing Now, other than the current song.
3. Press delete, or right click and select delete, or choose Edit > Delete . This will empty playing now, other than the current song.
4. Go to Method 1 or Method 2 depending on what you want.
This all might seem complicated, but it's really not. You can do this all very quickly and build the exact playlist you want, when you want.
Give it a try and let us know how it works for you.
Brian.
