It is not possible to select more than one message in message list with the "Unread" quick filter enabled.  As soon as you click on the first message for selection it instantly disappears from the message list rather than remaining selected.  Even if the intent is to only read new (unread) email messages individually the user is unable to determine which email message is currently selected in the message list. The bug renders Kmail almost useless for sorting a large number of incoming new messages or reading through threads.


Reproducible: Always

Steps to Reproduce:
1. Select Quick Filter "unread".
2. Attempt to select more than one email message by  holding down the shift or ctrl keys.
3. Attempt this same action with the "unread" quick filter disabled and note the difference. 




Expected Results:  
I expect for the current message to remain displayed in the message list until another filter is selected or some other action is performed, e.g. moving the message out of the current folder.