Message SAP WXP426 - Select a node in the tree control

Diagnosis
You have selected a processing function (for example, Explode nodes)that affect the selected nodes in the tree control.
The cursor has, however, been positioned outwith the tree control andthe function cannot, therefore, be executed.
INCLUDE ISR_VERARBEITUNG OBJECT DOKU ID TX

Procedure
Mark a node and call the function once again.