Summary task color blue or black?

Hello! Thanks for such a good software to plan projects.
After some little time of using ganttproject v2.8.10, win10, Spanish language…
… I would like to know why certain summary tasks colour is blue, instead of black.

I have search the forum and found nothing about this.
I have also searched the “user documentation” and found little on “the basics”.
thank you!

Because you set their color to “default” perhaps?
It would be nice to see an illustrating screenshot and/or project file.

Hello Dmitry! Thank you for your response.
Please take a look to the screenshot attached.

So, you said that I might have clicked on a specific property on the task to change color?
Thank you very much?
PD: I was wondering if the color assigment was related to properties as cost, or delay, or milestone associated.

Yes, I believe you reset color to default in the properties.