[bug] sky texture is removed after plotUpdate()

[jannessm]

Scenario:

• I initialize a visualizer with
  • adding a sky dome
  • set the camera position
• I add a tree
• I call plotUpdate() => here everything looks good
• I remove the leaves of the tree
• I call plotUpdate() => sky dome was removed

Expected behavior:

I assumed that after adding a sky dome it must be explicitly removed like all other primitives. But instead it gets somehow "removed".

Is this behavior on purpose?

Regards,
Jannes