The message windows allows you to edit messages without switching the current folder. Such you can work through your e-mails much faster. The calender serves as a quick reference. The week days are in German because my KDE was set to German at the time. In the folder pane of the main window you can see the new to do folder. Message in this folder are moved back into the inbox at a defined target date.
This is how you define the name and the default view of any folder. When the folder is active, the grid shows the columns seen in the right list box and sorts the messages after the fields in the sorting combo box.
Message can have a target date and time at which they are re-entered into the inbox and an alarm ist shown on the screen. This is very useful for delaying responses to a later time or even to organize your complete to-do list.