Release 10.1A: OpenEdge Development:
Progress 4GL Handbook

ENDKEY condition

The ENDKEY condition occurs when the user presses a keyboard key that is mapped to the ENDKEY keycode when input is enabled. It also occurs if an attempt to find a record fails or you reach the end of an input stream. Because your applications should not normally mix data input with transaction blocks in the same procedures, you do not frequently have cause to use the ON ENDKEY phrase on a transaction block.