I meant delete last part:
“Deleting Last Part: While Aeros is stopped on the Loop Studio Screen, using the
touchscreen, you can tap on the Song Part circle of the last song in the current
open song. This will pop up a dialog to delete the last part, hit “Yes” to confirm.
Note: This is NOT undoable and will delete the .wav files present in this song
part.”
This thread goes into some detail on how they want to use undo in place of deleted tracks (and improve the behavior of undone tracks to behave more like deleted tracks): Deleting track or part - #18 by BrennanSingularSound