After a second thought, I want to ask you a question:
You said that
the iLiad refreshes the screen and displays the .pdf document again
Did you mean that ipdf exited and then re-executed, or ipdf just didn't exit?
I guesss it should be the later case. Based on my understanding, ipdf started by contentlister will establish a ipc channel to communicate with contentlister, so that contentlister can pass NEWS, BOOKS, DOCS, NOTES and the two buttons above the flip-bar to ipdf. When ipdf is started by your application "A", maybe the IPC channel is not established, and you can't close ipdf by pressing the top-left key.
Well, these words are all conjecture. I don't know if they are correct.