[Error Marker] Overlapped error marker in graphical viewer

Whenever a error marker is displayed besides a graphical element in the statechart editor. the error marker might be overlapped by the name border of the parent control.

Steps to reproduce:

• Create a new statechart and add a second default entry to the statechart without connecting it to any other model element.
• Save the statechart
• An error marker should be displayed at the top right corner of the second default entry
• Move the previously created default entry closely under the name field of the main region
• The error marker disappears - also after saving the statchart
  The same behaviour can be reproduced for composite states and orthogonal states.

Expected behaviour:
The error markers are shown always at the top within the graphical editor