In email lists like when a folder is selected or in the Maintenance view, the markers (important, action) are hardly visible. Maybe a touch of color or just a colored bar in front of the email, a differently colored or underlined subject line etc. could help identifying emails that have been marked. Observed in version 4:4.5~20100827.1168757-1maemo1.1169941 .
It is corrected now. There is now a clearly visible transparent round icon at the start of the email subject in the Message List. The icon have a grey background and a white exclamation point for Mark as Important or 3 white dots for the Mark as Action Item. So I am closing this bug. Feel free to reopen if needed. N900, 4:4.6~20101112.1195992-1maemo1.1196001