The Key property returns the same value as the Add's Key parameter. The Key parameter of the Add method specifies the object to relate the note. The Key could be one of the following: 

• Key parameter is of Date type, it indicates the DATE in the chart to associate the note. By default, the RelativePosition property is 0.5, which indicates the center of the unit where the DATE is ( 0, means the start unit, while the 1 is the end of the unit, and so on ). The DateFromPoint property retrieves the date from the point.  By default, If a note is associated to a DATE, the RelativePostion property is 0.5, it displays only the ending part of the note, and the ending part of the note is not movable.
• Key parameter is not of Date type, it indicates the Key of the BAR to associate the note ( The Item and the Key indicates the bar to associate the note ). By default, the RelativePosition property is 0, which indicates the starting point of the bar  ( 0, means the starting point of the bar, while the 1 is the ending point of the bar, 0.5 indicates the middle of the bar, and so on ). The BarFromPoint property retrieves the key of the bar from the cursor.  By default, If a note is associated to a BAR, the RelativePostion property is 0, it displays only the ending part of the note, and the ending part of the note is not movable. Also, the direction from start to end part is visible. 

By default, the starting part of the note is not visible, so only the ending part of the note is visible.