docs: Don't hide the version selector when scrolling down

docs/extra.js

@@ -0,0 +1,22 @@
+document$.subscribe(function () {
+  // Stop mkdocs-material from hiding the version selector when scrolling down;
+  // this is done by removing the --active class when mkdocs-material adds it.
+  // (--active = scrolled down)
+
+  const title = document.querySelector('*[data-md-component="header-title"]');
+
+  const observer = new MutationObserver((mutations) => {
+    mutations.forEach((mutation) => {
+      if (mutation.attributeName === "class") {
+        const classList = title.className.split(" ");
+        classList.forEach((className) => {
+          if (className.endsWith("--active")) {
+            title.classList.remove(className);
+          }
+        });
+      }
+    });
+  });
+
+  observer.observe(title, { attributes: true });
+});

mkdocs.yml

@@ -84,6 +84,9 @@ markdown_extensions:
       emoji_index: !!python/name:material.extensions.emoji.twemoji
       emoji_generator: !!python/name:material.extensions.emoji.to_svg
 
+extra_javascript:
+  - extra.js
+
 # This lists all the files that become part of the documentation
 nav:
 - 'Home': 'index.md'