After we filter the message list to show only unread messages, using the state filter combo box, and we proceed to read the unread messages one by one, we verify that each message we select for reading gets removed from the message list, even though is still visible on the preview pane.

As the user decides on what to do with the message (ex: mark as unread) it becomes impossible to operate on the message via message list, since it is not visible anymore.

This is in wrong in terms of usability and UI consistency (there is a visual mismatch between the message list and the preview pane when that happens) and a regression from previous Kontact versions.

The selected message should stay visible in the message list until the user selects another one, except if the user marked it as unread again.

Reproducible: Always

Steps to Reproduce:
1. filter the message list to display only unread messages
2. click on an unread message
3. verify the its entry had disappeared from the message list
Actual Results:  
The message entry disappeared from the message list

Expected Results:  
The message entry should have remained on the message list.