Thank you! The first number was -980 (or similar)!

I have a little problem, 

it is impossible to use the "move" command to move mails from a folder to another one. When I'm in a folder and I select multiple messages (or just one), if I clic on them, Peggy runs and become insensitive, but I have to wait until I push ESC to work... 

It is the same when I clic "Set..." in the "Edit standard header rule".

It is with Win10, Pegasus Mail 4.73.639. 

Tanks a lot. 

The "Select a mail folder" window may be opening offscreen.  To fix this you need to
edit the STATE.PMJ file which is located in the home mailbox directory.

With Pegasus Mail closed, open STATE.PMJ in a text editor like Notepad and locate the the entry for "Select a mail folder=".  The value will be four number separated by commas.  These numbers represent the window location.  Change them to 48,148,420,527 then save the file.  Open Pegasus Mail and test.  The "Select a mail folder" window  should be visible.  You can reposition and resize to your liking.

If you don't know the home mailbox directory go to Pegasus Mail's main pull-down menu and select Help > About Pegasus Mail then press the Info button.  The resulting display will contain an entry showing the path to the home mailbox.