It would be excellent to be able to create/delete/manage custom map panes and then be able to specify which panes your layers get added to. This would allow fine tuned control over css changes to groups of layers at once, allow you to solve z-index issues, and this would even be an excellent solution for #1734.

What has brought about this, is that I use a lot of SVG objects on my map application. There are certain svg elements that I want to be above others all the time (with regards to z-index). However svg elements don't use z-index, and instead the elements added to the DOM last are the ones shown on top. The problem is that I add and remove a lot of the SVG elements to the map during normal usage of the mapping application. So this constantly changes which SVG elements are on top all the time.

Custom map panes would solve this problem and give the user a LOT more fine tuned control over their groups of layers and how they are displayed and interacted with.

Any thoughts on this?