Date options are not writable on task's propertiies

I make a project with several tasks and sub-tasks. After saving it nd opening in another day, I noticed that date options fields are not writable on task’s propertiies. I cannot find information about how to eliminate this situation. Thank you for the reading. Hope to have help in a short time.

Assuming that you’re talking about summary tasks, it works as designed. Please refer to this document for details: