You can make the updateable columns in your browse a different color. For example, you can make the read-only columns gray with black text and the updateable columns blue with yellow text. This code fragment assumes you defined variables to hold the standard color values:

ASSIGN CustNum:COLUMN-BGCOLOR IN BROWSE CustBrowse = gray-color
  CustNum:COLUMN-FGCOLOR IN BROWSE CustBrowse = black-color
  Name:COLUMN-BGCOLOR IN BROWSE CustBrowse = blue-color  
  Name:COLUMN-FGCOLOR IN BROWSE CustBrowse = yellow-color.
Note: In character interfaces, the COLUMN-DCOLOR attribute specifies the column color.