As the "correct behavior" in the bug link.
Also,
# Add two paint layers. Assume they are "Layer 1" and "Layer 2," from bottom to top.
# Add a clone layer copying from "Layer 1." Assume the clone is called "Layer 3."
# Move "Layer 3" below "Layer 1."
# In the layer docker, click on "Layer 1."
# Hold Ctrl, click on "Layer 2."
# Right click, then select "Remove Layer."
Expected: Layer 1 and Layer 2 are removed. Layer 3 turns into a Paint Layer.
# Undo.
Expected: Layer 1 and Layer 2 are restored. Layer 3 goes back into a Clone Layer.