When do 'When you play' effects trigger - as soon as you begin playing the card or after the card finishes resolving?

Ruling: 'When you play' effects trigger when the appropriate card finishes resolving.

Sequence:

• Play the card (e.g., Teemo from hidden)
• The unit instantly resolves
• Then 'When you play' triggers (e.g., Ember Monk) go on the chain
• You can order simultaneous triggers as you see fit

Nuances:

• The play effect goes on the same chain as the unit being played (matters for focus in showdowns)
• When a card finishes resolving doesn't mean its trigger has also resolved - the trigger still needs to resolve separately from the chain