My css isnt strong enough to fix this but the issue is coming from administrator\templates\atum\scss\blocks\_header.scss

  &.first:not(.last) {
    border-bottom-right-radius: 0;
    border-bottom-left-radius: 0;
  }

  &.last:not(.first) {
    border-top-left-radius: 0;
    border-top-right-radius: 0;
  }

  &:not(.first):not(.last) {
    border-radius: 0;
  }

it probably needs a class for :onlychild

Clicking on a line in editing / unpublishing a module - in the same place.

As of today, the "tip" for the menu module is NOT what is described by the OP.

I get here, when clicking on the down arrow

@infograf768 when you hover over the Author Menu you will see that it is then black with square corners

Oh, when hovering the tip to edit the module... Got it.

Sorry I reference the wrong scss file it should have been administrator\templates\atum\scss\vendor\bootstrap\_dropdown.scss

Please test #34059

Closing as having a pull request. Please test #34059 . Thanks in advance.