window-rule: open windowB upon/below(vertically) focused windowA

[AClon314]

Before:

______________
|file manager|
|  window A  |
|____________|

---

After:

______________
|  window A  |
|____________|
______________
| terminal B |
|____________|

[YaLTeR]

I'm not sure I understand, what behavior do you propose here exactly? Could you sketch out the window rule syntax and what exactly it will do?