How to simply close a tab? How can one close a tab in the Arduino IDE? There is a Tab button (little triangle) with the Option "Delete"(kind of misleading term). There is no "Close" option. And the "Delete" option doesnt do the job for me either, because the tabs are write-protected, and I just get a prompt.
You cannot close a tab in the Arduino IDE.  If a file exists in the sketch then it is there with a tab. Deleting a tab deletes the file.

In the Arduino IDE a tab is a file and a file is a tab. You can't remove one without removing the other.

You might like to check out my IDE, UECIDE, which deals with tabs in a more traditional manner.