I set up a machine with new Linux installation, along with a clean ~/.kde4 directory so that I would have no cruft from old user profiles. Once I set up accounts in KMail and started navigating my folders, I saw the following optical glitch.

For clarification I attached a screenshot which shows the same part of the screen for two different points in time. On the left you see what the message list looks like after I clicked on its entry in the folder list. The other half depicts how it looks after I moved the mouse into the message list. As you can see, some more status icons appeared.

It boils down to the "Message tags" item which can be added in the customisation dialogue for message list themes (the one which is shown using three tag icons). For a test I cloned the "Intelligent" theme and removed all other items on its right side except for "Message tags". As expected, only the message topic was now shown in the message list right after loading it. But when I moved the mouse in, some icons appeared.

As I mentioned, the KDE profile dir was empty from scratch, plus I don't use custom message tags at all. So this can't be a problem originating from left-overs from another installation.

Reproducible: Always

Steps to Reproduce:
1. Set message list theme to "itelligent" ("decorative" in earlier version).
2. Click on a folder to display its messages.
3. Move the mouse into the message list area.
Actual Results:  
Another set of message status icons appear during step 3.

Expected Results:  
The icons should not appear.