Layer Switcher - Nested Group Support

[davidtaddei]

Description The layer switcher only supports a single tier of nested groups. If a group is within a group then it's layers are duplicated and presented twice in the control.

To Reproduce Create a layer group (parent), add a nested group (child), add any layer to the child. Observe the child group being displayed beneath the parent and as a top tier level. Open the child group and observe that both entries are opened.

Expected Layer switcher should handle multiple nested groups

[Viglino]

That's not the case. Maybe you have add it twice... See: https://codepen.io/viglino/pen/dPbJwyJ