How To Fix EC126 - System functions cannot be defined in the standard toolbar

SAP Error Message - Details

• Message type: E = Error

• Message class: EC - Development environment: Menu Painter

• Message number: 126

• Message text: System functions cannot be defined in the standard toolbar

What causes this issue?

Certain icons in the standard toolbar cannot be assigned to functions.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

If you want to program the <LS>Possible entries</> or <LS>Help</>
functions yourself, you must include the events PROCESS ON HELP REQUEST
or PROCESS ON VALUE REQUEST in the screen flow logic and program the
relevant modules.
However, if you want to program both help functions, both icons must
have a function assigned in lists. To do this, you must change the type
of function key setting by selecting <LS>Goto -> Attributes -> F key
setting...</> and changing the type.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message EC126 - System functions cannot be defined in the standard toolbar ?

  The SAP error message EC126, which states "System functions cannot be defined in the standard toolbar," typically occurs when there is an attempt to add or modify system functions in the standard toolbar of an SAP GUI application. This is not allowed because the standard toolbar is reserved for predefined system functions that are integral to the SAP interface.
  Cause:
  
  Modification Attempt: The error is usually triggered when a user or developer tries to customize the standard toolbar by adding or changing system functions.
  Configuration Issues: It may also arise from incorrect configurations in the SAP GUI settings or in the application itself.
  
  Solution:
  
  Avoid Customization: Do not attempt to add or modify system functions in the standard toolbar. Instead, use custom toolbars or menus for any additional functionality you want to implement.
  Check Custom Code: If you are a developer, review any custom code or enhancements that may be trying to manipulate the standard toolbar. Ensure that you are not trying to add system functions there.
  Use Transaction Codes: If you need to access specific functions, consider using transaction codes or creating custom buttons in a custom toolbar instead of modifying the standard one.
  Consult Documentation: Refer to SAP documentation or help resources for guidelines on customizing toolbars and menus properly.
  
  Related Information:
  
  SAP Notes: Check SAP Notes for any updates or specific fixes related to this error. SAP frequently releases notes that address known issues.
  SAP Community: Engage with the SAP Community forums to see if other users have encountered similar issues and what solutions they have found.
  SAP GUI Version: Ensure that you are using a compatible version of the SAP GUI, as certain versions may have different capabilities or restrictions regarding toolbar customization.
  
  If the issue persists after following these steps, consider reaching out to your SAP support team or consulting with an SAP expert for further assistance.