Dynamic report selections in InputScript: Is there any special coding to allow GuiXT to interact with dynamic field selections?  I have recorded an InputScript for transaction LX10; it records fine but will not play back correctly for the tree operations of the dynamic selections.
The special controls such as tree control and calendar control cannot be handled with GuiXT. You may use SAP GUI scripting which you can call up from an InputScipt (command ApplyGUIScript, or CallVBS with component GuiXT controls).

But in some installations this is not a feasible solution since it requires that you activate SAP GUI scripting both on the server (SAP profile) and on the client (SAP GUI options).

A workaround in your case (transaction LX10)  is the following:

Define a report variant for the underlying ABAP report RLT10010  that contains the dynamic field selections you need. Instead of starting transaction LX10 in your InputScript, use transaction START_REPORT, enter the report name RLT10010 and the name of the variant that you have created, and execute "Enter" to start the report.