Users and Groups with write access to the repo do not have "Merge" button show up in pull request

When I setup the Branch permission to prevent developers to push or merge directly to the develop or master branches following Git Flow branch strategy, but able to merge via pull request, this is how I set it up as shown below.

When I didn't add anyone else to the "Users and Groups" field in "Merge via Pull request", a developer didn't see "Merge" button even though his group has a write permission to the repo as said in Picture BCLOUD-1.

Only when I added his group to that field, then he saw the merge button. Either that statement "*Includes users and groups with write access" is misleading or misconfigured.

Picture BCLOUD-1:

Oh! and one other issue: to add more users and groups, you have to carefully place the mouse point right between that last group and the edge of the field (maybe 1 pt space?). This UI is ridiculous. First time we clouds't figure out how to add more users and groups.