SAP Note 25373 - Field SY-DATAR has incorrect value

Symptom:

The value of the system field SY-DATAR is not correct.

Cause and prerequisites

This note is only relevant for application developers !
Before determining that the value of the field SY-DATAR is incorrect, you should note the following:

- the possible values of SY-DATAR and their description:

SPACE : no entries were made in the current screen

'X' : entries were made in the current screen

- The term "current screen" is the main screen as well as any
subscreens that may also exist. The field SY-DATAR is always
valid for all of this.

- As an entry for a screen, all the following processes are valid.
These lead to the field SY-DATAR being set:

manual entry via the keyboard

transferring a value via background input

transferring a value via GPA (get parameter)

distributing a held or set value (hold/set data)

supplying a value via transaction parameter

distributing a value into a global field (HD project)

setting a selection field by default (radio button)

transfer of a value via the possible entries pushbutton (F4).

Solution
Please note the above rules.