Block in navigation bar not displayed correctly

When I activate "main menu" and "secondary menu" in the parameters of my bootstrap theme, here is the display :

screenshot20170120_052544095.png

When I disable "main menu" and "secondary menu", and put the blocks "main menu" and "user menu" in the navigation bar, here is the display :

screenshot20170120_052725241.png

How to display the blocks correctly, as in the first screenshot ?

Thank you for your help