Well because she should have just used the cast screen (not tab) feature if you needed to switch between tabs?
Maybe you are unaware that casting the entire screen is still considered "experimental"? I don't know, not doing your research before responding sounds like something you would do
And its not considered experimental on just a regular chrome extension, it is considered experimental on a
beta version of a chrome extension.
This on my MBA doesn't work very well. And with my desktop and multiple monitors it is even worse.