I read Code editor screen reader accessiblity survey & check the codemirror options documentation, but I did not found any option or “guideline” to make CodeMirror allowing a user to exit from edition zone with key…
Did I miss something ? Do I need to implements it by myself ?
Do you mean not capturing the tab key? You can do something like passing an extraKeys: {Tab: false, "Shift-Tab": false} option to disable handling of tab and shift-tab. CodeMirror 6 doesn’t bind these keys by default for this reason (but I expect many sites will override that).