Look rotation viewing vector is zero spam in editor

Questions & Answers
1

After upgrading my project to 5.5 I started getting this error spamming the console. It only seem to happen when I have a gui element selected and am in scale mode in the editor. When selecting the object i get the message a few times then if my mouse cursor is over the scene view the console is filled with the same message, slowing the editor down and making it nearly unusable.

I recreated a small part of my gui and it is not happening with the remade parts.

Here is the full message:

“Look rotation viewing vector is zero
UnityEngine.Quaternion:LookRotation(Vector3, Vector3)
UnityEditorInternal.Slider2D:CalcDeltaAlongDirections(Int32, Vector3, Vector3, Vector3, Vector3, Vector3, Single, CapFunction, Vector2, Boolean) (at C:/buildslave/unity/build/Editor/Mono/EditorHandles/Slider2D.cs:279)
UnityEditorInternal.Slider2D:Do(Int32, Vector3, Vector3, Vector3, Vector3, Vector3, Single, CapFunction, Vector2, Boolean) (at C:/buildslave/unity/build/Editor/Mono/EditorHandles/Slider2D.cs:114)
UnityEditor.DockArea:OnGUI()”

2

It wasn’t in play mode for me too, just in editor.

And the trouble occurred because the size of My canvas was Zero…

3

For me, the issue happening when I would select a LayoutElement

Turned-out that the parent Vertical Layout Group had anchors collapsed and the height of the blue rectangle (press T to view rec transform tool) was 0

So I added the content size fitter to that layout group (and set it to follow the preffered height), which fixed the issue