The date cell handles the following accelrator keys:
'+':
'=': increment day
'_':
'-': decrement day
'}':
']': increment month
'{':
'[': decrment month
'M':
'm': begining of month
'H':
'h': end of month
'Y':
'y': begining of year
'R':
'r': end of year
'T':
't': today