In messages settings panel, you can define the connections between messages and messages and something else, looking at the following picture, then you may know what you can do here!

For the "Define the spacing (pixel) between two messages", when you enter a number in it and click the Save button, the effect will be as the following picture shows:

For the "The maximum smileys per message", when you enter a number (I entered "4") in it and click the Save button, the effect will be as the following picture shows: