Isaac Sim 6.0.0 dev2: AttributeError in omni.kit.viewport.menubar.camera during initialization

[lukas-durica]

Description

Isaac Sim 6.0.0 dev2 built from source.

I am seeing an initialization-time error in Isaac Sim 6.0.0 coming from the viewport camera menu extension. The error appears while the application is starting up / initializing the viewport, when a viewport camera/render settings notification is handled before context.camera_collection is available.

The failing line is:
context.camera_collection.checked = str(camera_path) not in SESSION_CAMERAS
resulting in:
AttributeError: 'NoneType' object has no attribute 'checked'

Full traceback:

2026-05-28T13:52:25Z [10,974ms] [Error] [omni.kit.widget.viewport.impl.utility] Traceback (most recent call last):
  File "/home/daco/Work/repositories/isaac-sim/extscache/omni.kit.widget.viewport-109.1.1+4a5123f4/omni/kit/widget/viewport/api.py", line 651, in __notify_objects
    fn(*args)
  File "/home/daco/Work/repositories/isaac-sim/extscache/omni.kit.viewport.menubar.camera-107.0.9+4a5123f4/omni/kit/viewport/menubar/camera/camera_menu_container.py", line 501, in __render_settings_changed
    self.__camera_changed(camera_path, viewport_api)
  File "/home/daco/Work/repositories/isaac-sim/extscache/omni.kit.viewport.menubar.camera-107.0.9+4a5123f4/omni/kit/viewport/menubar/camera/camera_menu_container.py", line 545, in __camera_changed
    context.camera_collection.checked = str(camera_path) not in SESSION_CAMERAS
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'checked'

Suggested fix:

Add a guard before accessing context.camera_collection, for example:

if context.camera_collection is not None:
    context.camera_collection.checked = str(camera_path) not in SESSION_CAMERAS

or ensure that __camera_changed() is not called until the camera collection UI object exists.

Isaac Sim version

6.0.0 dev2

Operating System (OS)

Ubuntu 24.04

GPU Name

RTX 4080

GPU Driver and CUDA versions

580.142

Logs

No response

Additional information

No response