The menu toggle button does not work on mobile when using Angular

[mhalttu]

When the screen is small, you see the "hamburger button" to toggle the sidebar visibility. In my Angular app, nothing happens when I tap the button. There are no errors in the console either - the button simply does not do anything.

Do you have any hints how to fix this?

[mhalttu]

I was able to get a bit further using the instructions at https://stackoverflow.com/questions/14741988/twitter-bootstrap-navbar-with-angularjs-collapse-not-functioning

<button type="button" class="navbar-toggle collapsed" (click)="toggleCollapse()" aria-expanded="false">

...

<div id="navbar" class="navbar-collapse" [class.collapse]="isCollapsed">

Tapping the button shows the menu now, but all the dropdown-toggle elements are also collapsed. If I tap them, they don't expand but simply act as links to "#". I don't want the dropdown elements collapsed in the first place.