While I had some severe problem with the doubleclick function of all my mouses I detected, that PM has no button or menu item for opening a listed message in its own window - which is default in all other Apple programs.
The only way to open a listed message in its own window is by double click this message on the folder list. Of course by enlarging the message-detail window downside of the folder list I found a way to read the message in a adequate way - but the possibility to open a message in his own window should be possible too - by menu item and/or button. This as a suggestion for the next update.
