Currently, when drawing an aggregation relation from one class (expected to contain the aggregation) to another class (which is supposed to be referenced), the aggregation diamond is placed at the wrong end. The standard says that it should be place at the class that contains the referenced element. In StarUML this would be the start of the aggregation line.
In the properties of the aggregation, one can change the end arrows and the type of relation ship. Doing this for all drawn aggregations makes no fun, so please change the default behavior of aggregation drawing to have the diamond at end1 and not at end2. Same applies to composition as well.