Index: simulator/run.py
===================================================================
diff -u -r69b2aacf31c5fdc28e078f87dbdee5c3ab672dd1 -r1779b6711f3791e8bf570e06ddb4c2e7d2a52e18
--- simulator/run.py	(.../run.py)	(revision 69b2aacf31c5fdc28e078f87dbdee5c3ab672dd1)
+++ simulator/run.py	(.../run.py)	(revision 1779b6711f3791e8bf570e06ddb4c2e7d2a52e18)
@@ -6,6 +6,7 @@
 from dialin.squish import utils
 from PySide2 import QtCore, QtWidgets
 from simulator.loader import Simulator
+from dialin.ui.hd_simulator import HDSimulator
 
 
 def main():
@@ -21,12 +22,26 @@
     simulator = Simulator()
     simulator.show()
 
+    hd_simulator_instance_counter_check()
+
     utils.tstDone()
 
     # start qt application main loop
     sys.exit(app.exec_())
 
 
+def hd_simulator_instance_counter_check():
+    """
+    Checks to make sure only one instance of the HDSimulator has been created.
+    this code shall be part of the HDSimulator __init__ but other codes are not ready for this.
+    so only the simulator is checking it now.
+    """
+    if HDSimulator.instanceCount > 1:
+        raise Exception("more than one instance of HDSimulator shall not be created.")
+    else:
+        print("HDSimulator number of instances is ", HDSimulator.instanceCount)
+
+
 if __name__ == "__main__":
     QtCore.QCoreApplication.setAttribute(QtCore.Qt.AA_ShareOpenGLContexts)
     main()