Clearing customer open items with reserved item cannot simulate General Ledger

When I use TCD：F-28or F-04 clear customer open items with reserved item，the text of clearing line is required item.

I typed in the text and click 【Simulate General Ledger】to check the text and other informations correct before post， but after simulating general Ledger，when I click 【post】button，the text I typed disappeared and I cannnot post the document.

If I do not Simulate General Ledger before post，I can post the document successfully.

The problem is I want to simulate general ledger to check all informations accurate and of course I need to post the document successfully.

Anybody know how to fix this issue?Thank you very much.