PO Print Preview opens up repeatedly after clicking one time

Hello everyone,

I have created a driver program to handle PO Print Preview. Configurations were also done on the transaction NACE. So as expected clicking on the Print Preview button the correct output is displayed.

But I am noticing a strange behavior. Sometimes after clicking the Print Preview button the preview shows up as expected, but when I exit out of the smartform display and click any other button in the PO interface, the smartform display popup comes up. Even exit-command such as back and cancel doesn't work.

I have never experienced something like this before. So I debugged and found out that the call to method get_fcode is returning the PREVOUTPUT fcode instead of the current sy-ucomm.

I found just another thread on here but even on that no specific solution was provided. So please help me if you can. The server I am working on has ECC6 on HANADB.