I'm not familiar with all the fundamental parts of the VS, so this will be a rookie question.
I somehow made those rectangles appear near line numbers and I don't even know what they are called. So,
- How do I make them disappear?
- How do I make them appear?
- What are they called and used for?
You may explain what they are used for if you feel like it, otherwise, providing the name will be sufficient for me to search my way through:)