
PASS slotchange event: Append a child to a host. 
PASS slotchange event: Remove a child from a host. 
PASS slotchange event: Remove a child before adding an event listener. 
PASS slotchange event: Change slot= attribute to make it un-assigned. 
PASS slotchange event: Change slot's name= attribute so that none is assigned. 
PASS slotchange event: Change slot= attribute to make it assigned. 
PASS slotchange event: Change slot's name= attribute so that a node is assigned to the slot. 
PASS slotchange event: Add a fallback content. 
PASS slotchange event: Remove a fallback content. 
PASS slotchange event: Add a fallback content to nested slots. 
PASS slotchange event: Remove a fallback content from nested slots. 
PASS slotchange event: Insert a slot before an existing slot. 
PASS slotchange event: Remove a preceding slot. 
PASS slotchange event: A slot is assigned to another slot. 
PASS slotchange event: Even if distributed nodes do not change, slotchange should be fired if assigned nodes are changed.