There is no obvious way to open note in horizontal split. All the available Ctrl/Cmd-click and Enter hotkeys are opening the file in vertical split.
The only way I have found so far is just to perform horizontal split and then open a note (not ideal, because the currently active note moves to the lower pane).
- Operating system: Catalina 10.15.4
- Obsidian version: 0.6.0
- Using custom CSS: no