Scrolling during a tour is buggy if height is set to 100% on body and html

If you style your Angular app's "body" and "html" tags with "height: 100%" and then start a tour, scrolling will partially work (just as the demo "shepherd-tester" in the repo), but if you scroll up and down a bit, scrolling will suddenly stop working and you might get stuck with the tour modal out of view.

So if you have

body, html {
    height: 100%;
}

in your styles.css, and want to use Angular Shepherd without the buggy scroll behavior, you need to find another way to make your app have full width/height with regards to the browser window.

One workaround that seems to work for me so far is:

styles.css

html, body {
  min-height: 100vh;
  margin: 0;
}
body {
  display: flex;
}

app.component.css

:host {
    flex: 1;
}

Reproduce the issue in the repository's shepherd-tester demo using html and body height: 100%, then inspect the tour's scrolling behavior. The work is done when repeated scrolling keeps the tour modal reachable instead of stopping with the modal out of view, without relying on the reported CSS workaround.