Fix multicursors not being added when clicking on line numbers

[neunato]

Closes #21372

Release Notes:

• Fixed multicursors not being added when clicking on line numbers

---

I tracked this down to

zed/crates/editor/src/element.rs

Line 591 in b6ee367

click_count = 3; // Simulate triple-click when clicking the gutter to select lines

being forwarded to editor.select() a few lines below

zed/crates/editor/src/element.rs

Lines 667 to 675 in b6ee367

	editor.select(
	SelectPhase::Begin {
	position,
	add: multi_cursor_modifier,
	click_count,
	},
	window,
	cx,
	);

resulting in add == true and click_count == 3, triggering this

zed/crates/editor/src/editor.rs

Lines 2750 to 2752 in b6ee367

	} else if click_count > 1 {
	s.delete(newest_selection.id)
	}

... and we end up removing the previous selection.

This was added in 2021 under this reasoning:

This prevents selections added in earlier clicks from being rendered under the pending selection.

which no longer seems to be an issue, so removing should be safe?

[SomeoneToIgnore]

Nice catch and investigation, thank you a lot for explaining.