Note that I'm testing using a keyboard with media buttons (Play/Pause, Stop, etc.) and using just the Enter/Ok and Arrow keys to duplicate a remote control functionality.
In Standard View, I can view the Smartlist by Album Thumbnail, and I will just see one thumbnail per Album.
When in Standard View, if I select an Album thumbnail and press Enter, just that Album is loaded into Playing Now and playback starts. I have the "Start playing when files added to Playing Now" setting ticked, which is why playback starts.
If I press Play/Pause, MC stops playback, and if I press Play/Pause again, MC restarts playback.
If tracks are playing and I press Stop, MC stops playback. When I then press Play/Pause, MC gives me the message "There is nothing to play", even though I can see the Album tracks in Playing Now in the second pane of my split view.
That was unexpected. I expected Play/Pause to restart playback after a Stop. But then I realised that is because I have the "General > Behaviour > Play button" set to "Play visible files". If I change that setting to "Play Playing Now" MC starts playback again after a Stop.
If nothing is playing with Playing Now empty and I press Play/Pause, I get the message "There is nothing to play", which I expected because I haven't selected anything to play.
All the above seems to be working as intended. I wanted to confirm all that before looking at Theatre View.
The reason for posting is that, in Theatre View, I can't get one thumbnail to display for each Album as I do in Standard View, no matter how I "Toggle list style". Are you getting one thumbnail per Album in Theatre View magnust? If so, how have you made that happen?
The reason this question is important is that without the equivalent of the "Album Thumbnail" view style in Theatre View, all displays of the Smartlist are Track based displays. So starting with Playing Now empty;
Pressing Play/Pause on any track in the Smartlist adds all tracks to Playing Now, and starts playback at the selected track. The Playing Now List view in Theatre View shows this, as does Playing Now if you switch back to Standard View.
Again with Playing Now empty, if a track is highlighted and Enter/Ok is pressed, then Play is selected from the top menu, just the one track is placed into Playing Now (or if Playing Now has content, it replaces that content with my settings), and playback of that track starts. When the track finishes, playback stops, leaving just the one track in Playing Now.
Again with Playing Now empty, if a track is highlighted and Enter/Ok is pressed, then "Play All" is selected from the top menu, or the Play/Pause button is pressed, the whole Smartlist is placed into Playing Now (or if Playing Now has content, it replaces that content with my settings), and playback of the highlighted track starts. When the track finishes the next track in the Smartlist starts playing.
All the above also seems to be working as intended.
So the real difference as far as I can tell is that Standard View allows Album based track selection, adding to Playing Now, and playback, while Theatre View is purely Track based selection, adding to Playing Now, and playback.
Unless you can explain how you are getting one Album thumbnail per Album in Theatre View, if you are. I would like to know, because then I might use Theatre View for audio playback more often, much like the way you are trying to use it.