ID 392102 - Adding a light to the GafferThree node without having a view node while in 3D Pen-up makes Katana unstable

Problem summary:
Adding a light to the GafferThree node without having a view node while in 3D Pen-up makes Katana unstable.

Steps to reproduce:
1. Add a GafferThree node and edit but don't view the node

2. Set your 3D mode to Pen-up

3. Add a light to the GafferThree

Expected behavior:
The light is added to the GafferThree node

Actual behavior:
Nothing appears to happen and then viewing the node causes a recursive error in the command line:

[WARN python.UI4.Tabs.SceneGraphView.BridgeImpl]: Scene graph child request callback <function executeCallback at 0x7fc3d0095488> returned None, but should return a boolean value to indicate whether it should be called again.

Using the Manual 3D Update Mode also causes the same error. Triggering 3D Update or Flushing caches creates a new light every time.

Workaround:
Use the Continuous 3D Update Mode or make sure you have a view node whenever adding lights.

Tested versions/platforms:

• Katana 3.1v4 - CentOS 7, Windows 10 - Affected
• Katana 3.1v3 - CentOS 7, Windows 10 - Affected
• Katana 3.1v2 - CentOS 7, Windows 10 - Unaffected
• Katana 3.1v1 - CentOS 7, Windows 10 - Unaffected