garbled mail window

Hello Members,

I have a strange issue with GW18 clients on multiple Windows 7 workstations. GW14R2 works fine, but after upgrading to GW18SP2, the compose or mail window gets garbled. It looks like the text from the hidden right side bar gets mixed up with the header. The attachment window on the bottom is missing. The "From", "To", "Subject" text is missing, but there is a "Change to" text overlapping with the actual subject of the email. I cannot reproduce it in my lab. Have you seen such behaviour?