Anchor navigation in panel not working properly with fixed header

[le0tan]

Tell us about your environment

• **MarkBind Version:**2.11.0

What did you do? Please include the actual source code causing the issue.

1. Fix the header with <header class="header-fixed"> in header.md
2. Include the following content

<panel header="## Hello">
</panel>

What did you expect to happen?

Anchor navigation on "Hello" should work properly.

What actually happened? Please include the actual, raw output.

Clicking the anchor would place the title under the top navbar.

[le0tan]

@marvinchin help wanted: looks like the dummy span is correctly inserted but why the navigation breaks in this case?

[marvinchin]

@le0tan Seems like const headingElement = document.getElementById(window.location.hash.slice(1)); is getting us the wrong element.