I've tried to include a Bootstrap responsive navbar (https://bootstrapdocs.com/v3.3.6/docs/components/#navbar-default) on a page using HTMLSnippet widget (I'm on Mendix 6.6) This doesn't seem to work although I have checked the project's Bootstrap.js has required plugins (e.g. collapse.js & transition.js + css) . I do not get the correct responsive behavior (collapsing menu) and cannot get the dropdown button on the navbar to work. I'd appreciate any comments/suggestions.
Have you tried using the mendix sidebar toggle button in your navigation layout?
Heres some documentation on layouts and the sidebar toggle button