I have not tried this under Linux, but have experienced the same problem under Windows. The cursor can be placed only in input/modifiable fields.
You are allowed to point the mouse cursor within an output field and then double-click. The double-click is treated as ENTER, but the cursor position is available in system variables. The cursor position can be used to determine the line number or specific field.
The mainframe technique of field/line selection via PF key is not possible. Field/line selection and PF key selection must be invoked separately.
Presuming that you are selecting a detail line for drill-down and the PF key determines which function to invoke, you can simulate the mainframe technique.
. Add a 1-character input field to each line. Then you can move the cursor to the selcted line and press a PF key.
. Upon ENTER, determine the postion of the cursor. Based on the postion, you can process normally or pop-up a window for PF key selection.
. Logically associate field columns in the detail lines with specific PF keys (via the POS function). The cursor position then provides the detail line to process, and the specific PF key.