Arcgis pro raster symbology stretch option is not working when I use custom and manually put maximum and minimum value?I cant lock these custom value.

[sarbanisaha]

Hi I tried to change the symbology of raster in arcgis pro 2.4.3.I used stretch option in custom mode..I gave maximum and minimum values..but there is no option to lock the values..It is not getting changed..plz give some solution