Hi,
I've got several problems with your ejDiagram control. First of all, connectors sometimes change their positions when you color the blocks. The second problem is that when you use irregular shaped block, the connector is attached to the rectangle taken by the block, not to the block itself. The last problem is that some blocks, for example "DataSource" disappear when you change its color.
Additionally I enclose jsplaygroundand and video with example of this situation:
Thanks in advance for solving my problem.