MSC: Coregion only uses message start point
When moving the coregion start/end, a mesaage is only included, when the start/tail of the message is (vertically) inside the coregion. If it's only the end/head, the message is not in the coregion.
When moving the coregion start/end, a mesaage is only included, when the start/tail of the message is (vertically) inside the coregion. If it's only the end/head, the message is not in the coregion.