How can I tackle the problem:
Look rotation viewing vector is zero?
Here is how I get it:
I add an Image from UI.
When the Image is added I click on it in the Hierarchy view.
When focus is on an Image I take the Canvas border and move it left.
I get the Exception.
Here are some screenshots of the process which takes place:
In the last screenshot I selected the Canvas and tried to focus on it by pressing F in the Scene view. As you can see I am not able to resize the canvas anymore. That means that I would have to create a new Canvas and copy everything into it, which is pretty tiresome and error prone. That is a reason I am concerned with the Exception. Will appreciate any attention.