diff --git a/src/hover.cpp b/src/hover.cpp
index 670b685..8093724 100644
--- a/src/hover.cpp
+++ b/src/hover.cpp
@@ -124,7 +124,10 @@ using Display_Range_Fn = String8_Node *(*)(Arena *, String8_Node *, const char *
 
 enum Hover_Section_Flags {
   HoverSec_None = 0,
+  // Hide = don't show at all, even the title
   HoverSec_HideIfNotHovered = 1,
+  // Collapse = only show the title
+  HoverSec_CollapseIfNotHovered = 2,
 };
 
 // Functor used by get_section_hover_info to describe the structure of a section and print data about it.
@@ -143,8 +146,11 @@ struct Sec_Hover_Fn {
   b8 read(T *val, u64 offset, u64 *size = nullptr) const
   {
     u64 nb = size ? *size : sizeof(T);
-    if (offset + nb > section.range.end())
+    if (offset + nb > section.range.end()) {
+      fprintf(stderr, "Trying to read bytes 0x%" PRIX64 "-0x%" PRIX64 " which are past the end of the section 0x%" PRIX64 "!\n", 
+              offset, offset + nb, section.range.end());
       return false;
+    }
 
     memcpy(val, data + offset, nb);
     return true;
@@ -161,11 +167,19 @@ struct Sec_Hover_Fn {
 
     sec_body_fn();
 
-    assert(cur_field_off >= sec_start);
+    // assert(cur_field_off >= sec_start);
+    if (cur_field_off < sec_start) {// TEMP DEBUG
+      fprintf(stderr, "Something wrong going on in %s!\n", title);
+      return;
+    }
+
     b8 hovered = off >= sec_start && off <= cur_field_off;
 
-    if (!hovered & (flags & HoverSec_HideIfNotHovered)) {
-      pop_str8_node_child(prev_desc, info.desc);
+    if (!hovered) {
+      if (flags & HoverSec_HideIfNotHovered)
+        pop_str8_node_child(prev_desc, info.desc);
+      else if (flags & HoverSec_CollapseIfNotHovered)
+        info.desc->first_child = info.desc->last_child = nullptr;
     } else if (display_grouped) {
       // if we're in display_grouped mode, we want to highlight the entire range of the section;
       u64 sec_len = cur_field_off - sec_start;
@@ -350,7 +364,12 @@ struct Sec_Hover_Fn {
   enum Frame_Type {
     Frame_INVALID,
     Frame_Record,
-    Frame_List
+    Frame_List,
+    Frame_COUNT
+  };
+
+  static constexpr const char *frame_type_str[Frame_COUNT] = {
+    "INVALID", "Record", "List"
   };
 
   Frame_Type frame_header(u64 &size, u32 *n_items = nullptr, const char *title = nullptr)
@@ -431,7 +450,7 @@ struct Sec_Hover_Fn {
       field_str8<u32>("Type Name: %s");
       field_str8<u32>("Type Alias: %s");
       field_str8<u32>("Description: %s");
-    }, HoverSec_HideIfNotHovered);
+    });
   }
 
   void column_desc(const char *title)
@@ -456,13 +475,15 @@ struct Sec_Hover_Fn {
         field_le<double>("Value Min: %f");
         field_le<double>("Value Max: %f");
       }
-    }, HoverSec_HideIfNotHovered);
+    });
   }
 
   void schema_description(const char *title)
   {
     titled_section(title, [this] {
-      frame<Frame_List>("Fields",        [this] (u32 idx) { field_desc(push_str8f(arena, "Field %u", idx).c()); });
+      frame<Frame_List>("Fields",        [this] (u32 idx) { 
+        field_desc(push_str8f(arena, "Field %u", idx).c()); 
+      });
       frame<Frame_List>("Columns",       [this] (u32 idx) { column_desc(push_str8f(arena, "Column %u", idx).c()); });
       frame<Frame_List>("Alias Columns", [this] (u32 idx) { 
         frame<Frame_Record>(push_str8f(arena, "Alias Column %u", idx).c(), [this] {
@@ -536,7 +557,7 @@ struct Sec_Hover_Fn {
 
   void cluster_group()
   {
-    frame<Frame_List>("Cluster Group", [this] (u32) {
+    frame<Frame_Record>("Cluster Group", [this] {
       field_le<u64>("Min Entry: %" PRIu64);
       field_le<u64>("Entry Span: %" PRIu64);
       field_le<u32>("N Clusters: %u");
@@ -577,7 +598,7 @@ struct Sec_Hover_Fn {
               b8 has_checksum = n_elems < 0;
               push_str8_node_child(arena, info.desc, "Has Checksum: %s", has_checksum ? "yes" : "no");
               locator("Element Locator");
-            }, HoverSec_HideIfNotHovered);
+            });
           }
 
           i64 n_cols;
@@ -593,12 +614,12 @@ struct Sec_Hover_Fn {
           if (n_cols >= 0)
             field_le<i32>("Compression Settings: %d");
         });
-      }, HoverSec_HideIfNotHovered);
+      });
     });
   }
 
   template <Frame_Type FType, typename F>
-  void frame(const char *title, F &&frame_body_fn, u64 sec_flags = 0)
+  void frame(const char *title, F &&frame_body_fn, u64 sec_flags = HoverSec_CollapseIfNotHovered)
   {
     u64 start_off = cur_field_off;
     u64 size;
@@ -606,8 +627,11 @@ struct Sec_Hover_Fn {
     titled_section(title, [this, title, start_off, &size, &frame_body_fn] {
       u32 n_items = 0;
       Frame_Type ftype = frame_header(size, &n_items);
-      if (ftype != FType)
+      if (ftype != FType) {
+        fprintf(stderr, "Frame %s was supposed to be of type %s but it's of type %s\n",
+                title, frame_type_str[FType], frame_type_str[ftype]);
         return;
+      }
 
       if constexpr (FType == Frame_List) {
         // Sadness here.
@@ -829,7 +853,6 @@ struct Sec_Hover_Fn {
         if (zipped) {
           // XXX: why -1?
           range("Compressed payload", section.range.len - section.post_size - sizeof(u64) - 1);
-          field_le<u64>("Checksum: 0x%" PRIX64);
         } else {
           envelope_preamble();
           // NOTE: flags in principle require a more complex handling, but for now they are unused,
@@ -839,8 +862,8 @@ struct Sec_Hover_Fn {
           field_str8<u32>("Description: %s");
           field_str8<u32>("ROOT version: %s");
           schema_description("Schema Description");
-          field_le<u64>("Checksum: 0x%" PRIX64);
         }
+        field_le<u64>("Checksum: 0x%" PRIX64);
       }, HoverSec_HideIfNotHovered);
     });
   }
@@ -857,20 +880,23 @@ struct Sec_Hover_Fn {
         if (zipped) {
           // XXX: why -1?
           range("Payload", section.range.len - section.post_size - sizeof(u64) - 1);
-          field_le<u64>("Checksum: 0x%" PRIX64);
         } else {
           envelope_preamble();
           // NOTE: flags in principle require a more complex handling, but for now they are unused,
           // so they're always occupying only 8 bytes.
           field_le<u64>("Flags: 0x%" PRIX64);
           field_le<u64>("Header checksum: 0x%" PRIX64);
-          schema_description("Schema Extension");
-          // NOTE: Column groups are currently unused, so this should always be empty
-          frame<Frame_List>("Column Groups", [] (u32) {});
-          frame<Frame_List>("Cluster Groups", [this] (u32) { cluster_group(); });
-          range("Payload", section.range.len - cur_field_off);
-          field_le<u64>("Checksum: 0x%" PRIX64);
+          frame<Frame_Record>("Schema Extension", [this] {
+            schema_description("Schema Extension");
+          });
+          frame<Frame_List>("Column Groups", [this] (u32) {
+            field_le<u32>("Column Id: %u");                  
+          });
+          frame<Frame_List>("Cluster Groups", [this] (u32) {
+            cluster_group();
+          });
         }
+        field_le<u64>("Checksum: 0x%" PRIX64);
       }, HoverSec_HideIfNotHovered);
     });
   }
@@ -898,13 +924,13 @@ struct Sec_Hover_Fn {
         if (zipped) {
           // XXX: why -1?
           range("Payload", section.range.len - section.post_size - sizeof(u64) - 1);
-          field_le<u64>("Checksum: 0x%" PRIX64);
         } else {
           envelope_preamble();
           field_le<u64>("Header checksum: 0x%" PRIX64);
           frame<Frame_List>("Cluster Summaries", [this] (u32) { cluster_summary(); });
           frame<Frame_List>("Clusters", [this] (u32) { cluster(); });
         }
+        field_le<u64>("Checksum: 0x%" PRIX64);
       }, HoverSec_HideIfNotHovered);
     });
   }