How to toggle to change Decimal Value Of Group Summary

hi,
How to toggle to change Decimal Value Of Group Summary
tried in this way but not working

Code:

[#Form : Group summary]
button : SetDecimalValue


[button: SetDecimalValue]
    Key         : ctrl+C
    Title     : "DecimalChange"
        Action     : Set : format:"decimal:2"

[Variable : SetDecimalValue]
    type : Logical

[System : Variable]
    SetDecimalValue : no

 

"format : " works on field level

 

yes
i want to change fields format using button
[#fieldSP ClDrAmtA]
format:"decimal:2"


[#fieldSP ClCrAmtA]
format:"decimal:2"

i want to play this code using button

 

Code:

[#Form : Group summary]
button : SetDecimalValue


[button: SetDecimalValue]
    Key         : ctrl+C
    Title     : "DecimalChange"
        Action     : Set : SetDecimalValue : NOT ##SetDecimalValue

[Variable : SetDecimalValue]
    type : Logical

[System : Variable]
    SetDecimalValue : no

[system : formula]

SetDecVal : If ##SetDecimalValue then "decimal:2" else "decimal:0"  ;; use this formula in those fields

;;like this

[#field:DSP ClDrAmtA]
format:@@SetDecVal


[#field:DSP ClCrAmtA]
format:@@SetDecVal

 

thanks you very much.
you saved my life