In version 14 the Menu became an Object, and this had a major impact on the way you work with it in WebSite X5.  This is explained in detail in the project conversion notes:

http://static.incomedia.eu/websitex5.com/pdf/EN/v13tov14EN.pdf

And also in the help file for the new 2019.1 version:

https://help.websitex5.com/en/v2019.1/pro/index.html?ogg_menu.htm

The option was also introduced of having the hamburger button displayed even at desktop resolution, where it is not strictly necessary.  However, you can switch this off as per the instructions above in the help file:

When there isn't enough space to display all the items, the menu is automatically replaced by the hamburger button. This also happens when the website is not responsive (indicated in Resolutions and Responsive Design). Remember, therefore, that the hamburger button can be used in desktop websites as an alternative to the traditional navigation menu.

▪Always display the Hamburger Button: this allows the Hamburger Button to always be displayed instead of the main Navigation Menu, regardless of whether the available space is large enough to accommodate the expanded view of all the options.