IntelliJ directory little blue dot label in maven

Question

So I'm working on a java/scala maven project in IntelliJ. I made a new directory, and filled it out with src and test stuff, but it's not behaving the same as other directories.

What does the little blue square mean? Is it important? How do I make my new directory (second one) behave the same?

Thanks in advance, sorry if this is a stupid question.

Answer 1

It means the folder is defined as an Intellij Module.

Complete list of Intellij icons: https://www.jetbrains.com/idea/help/symbols.html