1 files changed, 16 insertions, 3 deletions

diff --git a/src/content/dependencies/generatePageSidebar.js b/src/content/dependencies/generatePageSidebar.js
index 43015aa..d3b5558 100644
--- a/src/content/dependencies/generatePageSidebar.js
+++ b/src/content/dependencies/generatePageSidebar.js
@@ -19,14 +19,13 @@ export default {
     // Sticky mode controls which sidebar sections, if any, follow the
     // scroll position, "sticking" to the top of the browser viewport.
     //
-    // 'last' - last or only sidebar box is sticky
     // 'column' - entire column, incl. multiple boxes from top, is sticky
     // 'static' - sidebar not sticky at all, stays at top of page
     //
     // Note: This doesn't affect the content of any sidebar section, only
     // the whole section's containing box (or the sidebar column as a whole).
     stickyMode: {
-      validate: v => v.is('last', 'column', 'static'),
+      validate: v => v.is('column', 'static'),
       default: 'static',
     },
 
@@ -37,6 +36,16 @@ export default {
       type: 'boolean',
       default: false,
     },
+
+    // Provide to include all the HTML for the sidebar in place as usual,
+    // but start it out totally invisible. This is mainly so client-side
+    // JavaScript can show the sidebar if it needs to (and has a target
+    // to slot its own content into). If there are no boxes and this
+    // option *isn't* provided, then the sidebar will just be blank.
+    initiallyHidden: {
+      type: 'boolean',
+      default: false,
+    },
   },
 
   generate(slots, {html}) {
@@ -68,7 +77,11 @@ export default {
       attributes.add('class', 'all-boxes-collapsible');
     }
 
-    if (html.isBlank(slots.boxes)) {
+    if (slots.initiallyHidden) {
+      attributes.add('class', 'initially-hidden');
+    }
+
+    if (html.isBlank(slots.boxes) && !slots.initiallyHidden) {
       return html.blank();
     } else {
       return html.tag('div', attributes, slots.boxes);