Feature request: create a new session directly in a split pane (one-step)

Currently, opening a new session in a split pane requires two steps:

1. Create a new session (Cmd+N / "+ New session"), which opens in the current pane.
2. Cmd/Ctrl-click that session in the sidebar to move it into a split pane.

It would be great to have a one-step way to create a brand-new session that opens directly into a new split pane (e.g. a modifier-key variant of Cmd+N, or a right-click "Open in new split pane" option).