I’m not sure why this behavior, but in Atom I am seeing select line one time, select the line.
(although like other selections it has the cursor blinking at the end of the selection)
That works, it selects the line as expected.
However, when you perform the same select line operation, without deselecting, it increases the selection by adding the line below the current selection.
Each time the selection grows downward.
I have never seen this behavior on macOS in other editors, because select line normally figures out where the cursor or more accurately, the current selection range, and extends the selection range both to the right and left.
For a zero length selection, or no selection, this selects the line the cursor is on.
If the line is selected it should normally just kind of remain selected
If the selection extends across lines, it extends to the left of the selection start and to the right of the selection end.
If there is a disjoint multiple selection it behaves the same with each disjointed selection (potentially merging them in between if they share a line).
Is there any way to make this behave like normal Cocoa text system behavior?