|A Spiral Curriculum?|
My guess is that although they have been shown how to do this they have rarely had a real need. They are so used to using forward and back buttons they have continued using this skill, when using tabs would have served them so much better.
I wonder, now they can see they have been shown the purpose in a real context for a real reason for using it, whether the mud will stick. And if it does what does this say about how we teach?