2671291 - Number Range: Unable to create or delete intervals, button is missing

• An existing interval is to be inserted or removed from a Number Range object on SNUM/SNRO transaction > Interval Editing (F7):
  
• But ‘Insert Line’ and ‘Delete Line’ buttons are not offered:
  
  
  Output like this was expected (with available ‘Insert Line’ and ‘Delete Line’ buttons):
  

Image/data in this KBA is from SAP internal systems, sample data, or demo systems. Any resemblance to real data is purely coincidental. 

SAP NetWeaver

Insert Line, Delete Line, groups
SNUM, SNRO , KBA , BC-SRV-NUM , Number Range Management , Problem