When loggin in into AppStudio, the Username would be Display, It should be left centered, that the full username is visible - in that case it Looks not good, because on the left there is a lot of space where the Name could be placed and not cutted
That space is used to display your ArcGIS Online user profile picture:
Even if your profile picture is blank, the blank image is still displaying in that space.
To set your ArcGIS Online profile picture, follow there instructions:
Manage profile—ArcGIS Online Help | ArcGIS
Hannah
Then Display just a Symbol, that there could be photo - like in ArcGIS Online - than you know something could be there