Opening maildatabase shows grey screen

Hello,

When I open my maildatabase, either through the Welcome Pane or by Ctrl-O, the contents of my Inbox is not shown. Instead it presents a grey screen on the right hand side and “NotesMail Tile” as the description on its tab.

The left side (folder view) is shown okay, and when I there select Inbox its contents is shown correctly in the right hand pane. At that moment the title is also changed correctly to display “Firstname Lastname - Inbox”.

Ctrl-Shift-F9 etc did not help.

(Please note, I use 6.0.1 client with 5.x mailfile on server.)

Any ideas how to fix this phenomenon?