Multiple vertical masters

[piconova]

Description

When we use add_master dispatcher, it adds new master below existing masters. Can we make this behaviour configurable such that new master can be added in a vertical split. I have an ultrawide monitor and want 2 masters vertically split and third slave stack.

Current Behavior (with horizontal split)

|       | s |          |   M   | s |
|   M   | s |     ->   |-------| s |
|       | s |          |   M   |   |

New Behavior (with vertical split)

|       | s |          |   |   | s |
|   M   | s |     ->   |   |   | s |
|       | s |          | M | M |   |