It didn't happen to me but happened to someone in our group, I also found a similar postquestion posted a year ago about the same bug, but there were no answers to that post didn't have any conclusions as well.question either (or atleastat least something that would fix it)
The Similar Post: Header buttons missing!
This happened after Blender 4.0 was installed. We checked if some checkboxes are off and re-installed Blender 4.0 as well. Still nothing.
Any help would be appreciated!
Edit: This is my first postquestion here, If Iif I've made any mistakes, I wouldwill gladly correct itthem!