Message type: E = Error
Message class:  E_ACTION - E-Actions 
Message number: 005
Message text: Dropdown or "F4" field's datatype should be "CHAR" or "NUMC".
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The SAP error message E_ACTION005 indicates that there is an issue with the data type of a field that is expected to be a dropdown (or F4 help) field. Specifically, the error states that the datatype of the field should be either "CHAR" (character) or "NUMC" (numeric character). This error typically arises in the context of screen fields, particularly when defining or using input fields in SAP GUI or in custom development.
Cause: Incorrect Data Type: The field in question is defined with a data type that is not compatible with dropdowns or F4 help. For example, it might be defined as a data type like "DATE", "TIME", or any other type that does not conform to the expected "CHAR" or "NUMC". Field Definition Issues: The field may have been incorrectly defined in the data dictionary (DDIC) or in the screen painter. Custom Development: If you are working with custom programs or enhancements, the
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