How to span the “panel” across multiple monitors?

[hurryman2212]

 * slick-greeter version: 2.0.1
 * Distribution: Xubuntu 24.04
 * Graphics hardware *and* driver used: Radeon W6400 (amdgpu)
 * 64 bit (x86-64)

Issue

Don’t know how to (and whether it supports to) span the upper panel across multiple monitors

Steps to reproduce

N/A

Expected behaviour

(if it supports) By enabling the option, the upper panel must span across the monitors.

Other information

I don’t know whether it supports the feature or not but have not been able to find reference about it.