Describe the bug
The following error is reported occasionally when opening telemetry pages:

  File "/export/home/jhageman/cFS/cFS-GitHub/tools/cFS-GroundSystem/Subsystems/tlmGUI/GenericTelemetry.py", line 108, in processPendingDatagrams
    self.displayTelemetryItem(datagram, k, itemLabel, itemValue)
  File "/export/home/jhageman/cFS/cFS-GitHub/tools/cFS-GroundSystem/Subsystems/tlmGUI/GenericTelemetry.py", line 66, in displayTelemetryItem
    TlmField2 = datagram[itemStart:itemStart +
UnboundLocalError: local variable 'itemStart' referenced before assignment

To Reproduce
Start cFS-GroundSystem, "Start Telemetry System", and I triggered it by opening the "Display Page" for "TBL HK Tlm". Page closed after error was produced.

Expected behavior
Page should open and display telemetry.

Code snips
Haven't tracked down yet

System observed on:

• Hardware: cFS Dev Server
• OS: Ubuntu 18.04
• Versions: Bundle main

Additional context
None

Reporter Info
Jacob Hageman - NASA/GSFC