The behaviour you noticed relates to the way how the Modelling Toolkit interacts with the database and backend services. When starting the modelling toolkit, the so-called CORE is initialized, meaning that the implementation as stored in the database is retrieved, interpreted and constructed in the modelling toolkit. This results in a stable "snap-shot" of the implementation.
Changes in the implementation within the development toolkit are stored first in the database, and available in the modelling toolkit as soon as you restart the modelling toolkit (retrieve, interprete, construct).