Claws mail configuration to use two panes layout

Claws mail configuration to use two panes layout

Is it possible to remove the preview pane in claws mail? I mean to have
only two panes: Left with the folder tree and right with the e-mail list.
Then when I double click on the message or press Enter key, separate
window with the message has to be opened.
It seems the whole functionality is already in Claws - it can open the
messages in separate window. But I can't figure out how to remove the
preview pane.
I know it was possible in Sylpheed though.