Now, whenever you receive a new message in that app, you'll no longer see a Bubble. When an app supports Bubbles, you'll see a little icon in the ... Tap "Manage" under the pop-up window.

However, you can choose to have new messages spawn Pop-Up View bubbles instead of Chat Bubbles ... tap on the app icon above the preview, and select Open in Pop-Up View. It will shrink into ...