I just changed the layout to "show message preview pane next to message list" and "short folder list". If I resize the entire window horizontally, only the left section (folder list and message list) resizes, the message preview pane stays the same size. Reproducible: Always Steps to Reproduce: Settings->configure Kmail>Layout Set "Folder List" to "Short folder List" and "Message preview pane" to "Show the message preview pane next to the message list" Then, resize the window horizontally Actual Results: The width of the left section changes the width of the message preview pane stays the same Expected Results: It should be the other way round