A save operation for a project (Ctrl + S) saves all scenario files even if no changes were made
This led to a problem in commit 3505a760. This commit introduced a new variable renderer
into Pedestrian
class. This variable was serialized immediately, but not deserialized properly (an exception occurred in scenario "rimea_06_corner_osm2.scenario" because this scenario already contained some Pedestrians).
First, document that new variables (in serialized classes) should be marked with annotation @JsonIgnoreProperties(value={"<variable_name>"})
if this variable should not be serialized. Then, discuss if it is really necessary to save each scenario file again when saving a project.