diff --git a/src/render.cpp b/src/render.cpp
index 99b2929..9341566 100644
--- a/src/render.cpp
+++ b/src/render.cpp
@@ -1,3 +1,19 @@
+internal
+std::optional<Byte_Range> get_section_range(const App_State &app, Section_Id sec)
+{
+  switch (sec) {
+    default: return {};
+    case Sec_TFile_Header:   return Byte_Range { 0, app.tfile_data.root_file_header_size };
+    case Sec_TFile_Object:   return app.tfile_data.rng_root_file_obj;
+    case Sec_TFile_Info:     return app.tfile_data.rng_root_file_info;
+    case Sec_TFile_FreeList: return app.tfile_data.rng_root_file_free;
+    case Sec_TKey_List:      return app.rndata.rng_tkeys_list;
+    case Sec_RNTuple_Anchor: return app.rndata.rng_anchor;
+    case Sec_RNTuple_Header: return app.rndata.rng_header;
+    case Sec_RNTuple_Footer: return app.rndata.rng_footer;
+  }
+}
+
 internal
 void accum_dt_ms(Delta_Time_Accum &accum, f32 dt)
 {
@@ -31,72 +47,62 @@ String8 to_pretty_size(Arena *arena, u64 bytes)
 }
 
 internal
-u32 mem_edit_bg_color_fn(const u8 *, u64 off, void *user_data)
+Section find_section(App_State &app, u64 off)
 {
-  App_State *app = reinterpret_cast<App_State *>(user_data);
-  const RNTuple_Data &rdata = app->rndata;
-  const TFile_Data &tdata = app->tfile_data;
+  const RNTuple_Data &rdata = app.rndata;
+  const TFile_Data &tdata = app.tfile_data;
   u64 rblob_sz = rdata.rblob_header_size; // @Incomplete
-  i64 hilite_cluster = app->viewer.highlight_cluster ? app->viewer.highlighted_cluster : -1;
+  i64 hilite_cluster = app.viewer.highlight_cluster ? app.viewer.highlighted_cluster : -1;
+  b8 hilite = false;
 
-  off += app->viewer.base_display_addr;
-
-#define COL(c) (ImColor((c)[0], (c)[1], (c)[2]))
   // TFile start
-  if (off <= tdata.root_file_header_size) return COL(app->viewer.col_tfile_header);
-  if (tdata.rng_root_file_obj.start <= off && off < tdata.rng_root_file_obj.end()) return COL(app->viewer.col_tfile_obj);
-  if (tdata.rng_root_file_info.start <= off && off < tdata.rng_root_file_info.end()) return COL(app->viewer.col_tfile_info);
-  if (tdata.rng_root_file_free.start <= off && off < tdata.rng_root_file_free.end()) return COL(app->viewer.col_tfile_free);
+  if (off <= tdata.root_file_header_size) return { Sec_TFile_Header, { 0, tdata.root_file_header_size }, 0, hilite };
+  if (tdata.rng_root_file_obj.start <= off && off < tdata.rng_root_file_obj.end())   return { Sec_TFile_Object, tdata.rng_root_file_obj, 0, hilite };
+  if (tdata.rng_root_file_info.start <= off && off < tdata.rng_root_file_info.end()) return { Sec_TFile_Info, tdata.rng_root_file_info, 0, hilite };
+  if (tdata.rng_root_file_free.start <= off && off < tdata.rng_root_file_free.end()) return { Sec_TFile_FreeList, tdata.rng_root_file_free, 0, hilite };
 
-  // Handle pages
-  // fast case: `off` is in the same page info as previous `off`.
-  if (app->last_pinfo->range.start < off && off < app->last_pinfo->range.end()) {
-    if (hilite_cluster >= 0 && app->last_pinfo->cluster_id == (u64)hilite_cluster)
-      return COL(app->viewer.col_highlight);
-    if (off >= app->last_pinfo->range.end() - app->last_pinfo->checksum_size())
-      return COL(app->viewer.col_checksum);
-    return COL(app->viewer.col_page);
+  /// Handle pages
+  {
+    // fast case: `off` is in the same page info as previous `off`.
+    if (app.last_pinfo->range.start < off && off < app.last_pinfo->range.end()) {
+      hilite = hilite_cluster >= 0 && app.last_pinfo->cluster_id == (u64)hilite_cluster;
+      return { Sec_Page, app.last_pinfo->range, app.last_pinfo->checksum_size(), hilite };
+    }
+
+    // still fast case: `off is in the next page info as the previous.
+    if (app.last_pinfo->next) // don't check if it's checksum, since it's the first byte of the page
+      app.last_pinfo = app.last_pinfo->next;
+    if (app.last_pinfo && app.last_pinfo->range.start <= off && off < app.last_pinfo->range.end()) {
+      hilite = hilite_cluster >= 0 && app.last_pinfo->cluster_id == (u64)hilite_cluster;
+      return { Sec_Page, app.last_pinfo->range, app.last_pinfo->checksum_size(), hilite };
+    }
   }
 
-  // still fast case: `off is in the next page info as the previous.
-  if (app->last_pinfo->next) // don't check if it's checksum, since it's the first byte of the page
-    app->last_pinfo = app->last_pinfo->next;
+  if (rdata.rng_anchor_key.start <= off && off < rdata.rng_anchor.end())
+    return { Sec_RNTuple_Anchor, rdata.rng_anchor, 8, hilite };
 
-  if (app->last_pinfo && app->last_pinfo->range.start <= off && off < app->last_pinfo->range.end()) {
-    if (hilite_cluster >= 0 && app->last_pinfo->cluster_id == (u64)hilite_cluster)
-      return COL(app->viewer.col_highlight);
-    if (off == app->last_pinfo->range.start)
-      return COL(app->viewer.col_page_start);
-    if (off >= app->last_pinfo->range.end() - app->last_pinfo->checksum_size())
-      return COL(app->viewer.col_checksum);
-    return COL(app->viewer.col_page);
-  }
+  if (rdata.rng_header.start - rblob_sz <= off && off < rdata.rng_header.end()) 
+    return { Sec_RNTuple_Header, rdata.rng_header, 8, hilite };
 
-  if (rdata.rng_anchor_key.start <= off && off < rdata.rng_anchor_key.end()) return COL(app->viewer.col_key);
-  if (rdata.rng_anchor.start <= off && off < rdata.rng_anchor.end() - 8)     return COL(app->viewer.col_anchor);
-  if (rdata.rng_anchor.end() - 8 <= off && off < rdata.rng_anchor.end())     return COL(app->viewer.col_checksum);
+  if (rdata.rng_footer.start - rblob_sz <= off && off < rdata.rng_footer.end())
+    return { Sec_RNTuple_Footer, rdata.rng_footer, 8, hilite };
 
-  if (rdata.rng_header.start - rblob_sz <= off && off < rdata.rng_header.start) return COL(app->viewer.col_key);
-  if (rdata.rng_header.start <= off && off < rdata.rng_header.end() - 8)        return COL(app->viewer.col_header);
-  if (rdata.rng_header.end() - 8 <= off && off < rdata.rng_header.end())        return COL(app->viewer.col_checksum);
-
-  if (rdata.rng_footer.start - rblob_sz <= off && off < rdata.rng_footer.start) return COL(app->viewer.col_key);
-  if (rdata.rng_footer.start <= off && off < rdata.rng_footer.end() - 8)        return COL(app->viewer.col_footer);
-  if (rdata.rng_footer.end() - 8 <= off && off < rdata.rng_footer.end())        return COL(app->viewer.col_checksum);
-
-  if (rdata.rng_tkeys_list.start <= off && off < rdata.rng_tkeys_list.end())    return COL(app->viewer.col_tkeys_list);
+  if (rdata.rng_tkeys_list.start <= off && off < rdata.rng_tkeys_list.end()) 
+    return { Sec_TKey_List, rdata.rng_tkeys_list, 0, hilite };
 
   // @Speed
   for (u64 cg_idx = 0; cg_idx < rdata.n_cluster_groups; ++cg_idx) {
     Cluster_Group_Info &cg_info = rdata.cluster_groups[cg_idx];
-    if (cg_info.rng_page_list.start -rblob_sz <= off && off < cg_info.rng_page_list.start) return COL(app->viewer.col_page_list);
-    if (cg_info.rng_page_list.start <= off && off < cg_info.rng_page_list.end() - 8)       return COL(app->viewer.col_page_list);
-    if (cg_info.rng_page_list.end() - 8 <= off && off < cg_info.rng_page_list.end())       return COL(app->viewer.col_checksum);
+    if (cg_info.rng_page_list.start - rblob_sz <= off && off < cg_info.rng_page_list.end())
+      return { Sec_Page_List, cg_info.rng_page_list, 8, hilite };
   }
 
   // Slow page group lookup, ideally only done once per render when last_pinfo is invalid.
   for (Page_Info_Chunk *chunk = rdata.page_chunks; chunk; chunk = chunk->next) {
-    if (chunk->range.start - rblob_sz <= off && off < chunk->range.start) return COL(app->viewer.col_key);
+    // If we're at the start of a chunk, return a fake Sec_Page used to highlight the RBlob header bytes. 
+    if (chunk->range.start - rblob_sz <= off && off < chunk->range.start)
+      return { Sec_Page, { chunk->range.start, 0 }, 0, hilite };
+
     if (chunk->range.start <= off && off < chunk->range.end()) {
       for (u64 group_idx = chunk->first_group; group_idx < rdata.n_page_groups; ++group_idx) {
         const Page_Info_Group &group = rdata.page_groups[group_idx];
@@ -105,11 +111,9 @@ u32 mem_edit_bg_color_fn(const u8 *, u64 off, void *user_data)
 
         for (Page_Info_Node *pinfo = group.first; pinfo; pinfo = pinfo->next) {
           if (pinfo->range.start <= off && off < pinfo->range.end()) {
-            app->last_pinfo = pinfo;
-            if (hilite_cluster >= 0 && pinfo->cluster_id == (u64)hilite_cluster) return COL(app->viewer.col_highlight);
-            if (pinfo->range.start == off)                                       return COL(app->viewer.col_page_start);
-            if (off >= pinfo->range.end() - pinfo->checksum_size())              return COL(app->viewer.col_checksum);
-            return COL(app->viewer.col_page);
+            app.last_pinfo = pinfo;
+            hilite = hilite_cluster >= 0 && pinfo->cluster_id == (u64)hilite_cluster;
+            return { Sec_Page, pinfo->range, pinfo->checksum_size(), hilite };
           }
         }
       }
@@ -119,9 +123,25 @@ u32 mem_edit_bg_color_fn(const u8 *, u64 off, void *user_data)
       assert(false);
     }
   }
-#undef COL
 
-  return IM_COL32(0, 0, 0, 0);
+  return {};
+}
+
+internal
+u32 mem_edit_bg_color_fn(const u8 *, u64 off, void *user_data)
+{
+  App_State *app = reinterpret_cast<App_State *>(user_data);
+  off += app->viewer.base_display_addr;
+
+  Section section = find_section(*app, off);
+  
+#define COL(c) (ImColor((c)[0], (c)[1], (c)[2]))
+  if (section.highlighted) return COL(app->viewer.col_highlight);
+  if (section.id == Sec_Page && off == section.range.start) return COL(app->viewer.col_page_start);
+  if (off < section.range.start) return COL(app->viewer.col_key);
+  if (section.range.end() - section.post_size <= off && off < section.range.end()) return COL(app->viewer.col_checksum);
+  return COL(app->viewer.col_section[section.id]);
+#undef COL
 }
 
 internal
@@ -152,21 +172,23 @@ void make_viewer(App_State &app)
   viewer.mem_edit = make_memory_editor(app);
 
 #define COL(c, r, g, b) viewer.c[0] = r/255.0, viewer.c[1] = g/255.0, viewer.c[2] = b/255.0
-  COL(col_anchor, 150, 150, 0);
-  COL(col_header, 150, 0, 50);
-  COL(col_footer, 50, 0, 150);
   COL(col_key,    0, 100, 50);
-  COL(col_tfile_header,  90, 90, 90);
-  COL(col_tfile_obj,  120, 120, 120);
-  COL(col_tfile_info, 95, 76, 76);
-  COL(col_tfile_free, 60, 60, 90);
-  COL(col_page,   125, 0, 125);
   COL(col_page_start, 200, 0, 200);
   COL(col_checksum, 134, 65, 25);
-  COL(col_page_list, 60, 110, 120);
-  COL(col_tkeys_list, 100, 140, 100);
   COL(col_highlight, 190, 190, 190);
+#define COL_S(c, r, g, b) viewer.col_section[c][0] = r/255.0, viewer.col_section[c][1] = g/255.0, viewer.col_section[c][2] = b/255.0
+  COL_S(Sec_RNTuple_Anchor, 150, 150, 0);
+  COL_S(Sec_RNTuple_Header, 150, 0, 50);
+  COL_S(Sec_RNTuple_Footer, 50, 0, 150);
+  COL_S(Sec_TFile_Header,  90, 90, 90);
+  COL_S(Sec_TFile_Object,  120, 120, 120);
+  COL_S(Sec_TFile_Info, 95, 76, 76);
+  COL_S(Sec_TFile_FreeList, 60, 60, 90);
+  COL_S(Sec_Page,   125, 0, 125);
+  COL_S(Sec_Page_List, 60, 110, 120);
+  COL_S(Sec_TKey_List, 100, 140, 100);
 #undef COL
+#undef COL_S
 
   app.viewer = viewer;
 }
@@ -282,65 +304,31 @@ void update_and_render(Arena *arena, App_State &app, f32 delta_time_ms)
       ImGui::TableNextColumn();
       ImGuiColorEditFlags flags =  ImGuiColorEditFlags_NoInputs|ImGuiColorEditFlags_NoLabel;
 
-      ImGui::ColorEdit3("_TFile Header",   app.viewer.col_tfile_header,  flags);
-      ImGui::SameLine(); 
-      if (ImGui::Button("TFile Header"))   viewer_jump_to(app.viewer, 0);
-      ImGui::SameLine(); 
-      ImGui::Text("%s", to_pretty_size(scratch.arena, app.tfile_data.root_file_header_size).c());
+      // Unique sections: just display a button that jumps to the start of it and show their size
+      for (u32 i = 0; i < Sec_COUNT; ++i) {
+        std::optional<Byte_Range> range = get_section_range(app, static_cast<Section_Id>(i));
+        if (!range) continue;
 
-      ImGui::ColorEdit3("_TFile Object",   app.viewer.col_tfile_obj,  flags);
-      ImGui::SameLine(); 
-      if (ImGui::Button("TFile Object"))   viewer_jump_to(app.viewer, app.tfile_data.rng_root_file_obj.start);
-      ImGui::SameLine(); 
-      ImGui::Text("%s", to_pretty_size(scratch.arena, app.tfile_data.rng_root_file_obj.len).c());
-
-      ImGui::ColorEdit3("_TFile Info",   app.viewer.col_tfile_info,  flags);
-      ImGui::SameLine(); 
-      if (ImGui::Button("TFile Info"))   viewer_jump_to(app.viewer, app.tfile_data.rng_root_file_info.start);
-      ImGui::SameLine(); 
-      ImGui::Text("%s", to_pretty_size(scratch.arena, app.tfile_data.rng_root_file_info.len).c());
-
-      ImGui::ColorEdit3("_TFile FreeList",   app.viewer.col_tfile_free,  flags);
-      ImGui::SameLine(); 
-      if (ImGui::Button("TFile FreeList"))   viewer_jump_to(app.viewer, app.tfile_data.rng_root_file_free.start);
-      ImGui::SameLine(); 
-      ImGui::Text("%s", to_pretty_size(scratch.arena, app.tfile_data.rng_root_file_free.len).c());
-
-      ImGui::ColorEdit3("_TKey List", app.viewer.col_tkeys_list, flags);
-      ImGui::SameLine(); 
-      if (ImGui::Button("TKey List"))      viewer_jump_to(app.viewer, app.rndata.rng_tkeys_list.start);
-      ImGui::SameLine(); 
-      ImGui::Text("%s", to_pretty_size(scratch.arena, app.rndata.rng_tkeys_list.len).c());
-
-      ImGui::ColorEdit3("_RNTuple Anchor", app.viewer.col_anchor, flags);
-      ImGui::SameLine(); 
-      if (ImGui::Button("RNTuple Anchor")) viewer_jump_to(app.viewer, app.rndata.rng_anchor.start);
-      ImGui::SameLine(); 
-      ImGui::Text("%s", to_pretty_size(scratch.arena, app.rndata.rng_anchor.len).c());
-
-      ImGui::ColorEdit3("_RNTuple Header", app.viewer.col_header, flags);
-      ImGui::SameLine(); 
-      if (ImGui::Button("RNTuple Header")) viewer_jump_to(app.viewer, app.rndata.rng_header.start);
-      ImGui::SameLine(); 
-      ImGui::Text("%s", to_pretty_size(scratch.arena, app.rndata.rng_header.len).c());
-
-      ImGui::ColorEdit3("_RNTuple Footer", app.viewer.col_footer, flags);
-      ImGui::SameLine(); 
-      if (ImGui::Button("RNTuple Footer")) viewer_jump_to(app.viewer, app.rndata.rng_footer.start);
-      ImGui::SameLine(); 
-      ImGui::Text("%s", to_pretty_size(scratch.arena, app.rndata.rng_footer.len).c());
-
-      ImGui::ColorEdit3("_TKey Header",    app.viewer.col_key,    flags);
-      ImGui::SameLine(); 
-      if (ImGui::Button("TKey Header"))    {} // TODO jump to next key
+        String8 sec_name = section_names[i];
+        String8 col_label = push_str8f(scratch.arena, "_%s", sec_name.c());
+        ImGui::ColorEdit3(col_label.c(), app.viewer.col_section[i], flags);
+        ImGui::SameLine(); 
+        if (ImGui::Button(sec_name.c())) 
+          viewer_jump_to(app.viewer, range->start);
+        ImGui::SameLine(); 
+        ImGui::Text("%s", to_pretty_size(scratch.arena, range->len).c());
+      }
 
+      // Repeated sections: allow jumping to the N-th
       ImGui::ColorEdit3("_Page Start", app.viewer.col_page_start, flags);
       ImGui::SameLine(); 
-      if (ImGui::Button("Page Start"))     viewer_jump_to_page(app, 0);
+      if (ImGui::Button("Page Start"))
+        viewer_jump_to_page(app, 0);
 
-      ImGui::ColorEdit3("_Page", app.viewer.col_page, flags);
+      ImGui::ColorEdit3("_Page", app.viewer.col_section[Sec_Page], flags);
       ImGui::SameLine();
-      if (ImGui::Button("Page"))           viewer_jump_to_page(app, app.viewer.latest_page_gone_to);
+      if (ImGui::Button("Page"))
+        viewer_jump_to_page(app, app.viewer.latest_page_gone_to);
       ImGui::SameLine();
       {
         const i64 step_fast_i64 = app.rndata.n_pages / 100;
@@ -357,7 +345,7 @@ void update_and_render(Arena *arena, App_State &app, f32 delta_time_ms)
       ImGui::SameLine(); 
       if (ImGui::Button("Checksum")) {} // TODO jump to next checksum
 
-      ImGui::ColorEdit3("_Page List", app.viewer.col_page_list, flags);
+      ImGui::ColorEdit3("_Page List", app.viewer.col_section[Sec_Page_List], flags);
       ImGui::SameLine(); 
       if (ImGui::Button("Page List"))      viewer_jump_to_page_list(app, app.viewer.latest_page_list_gone_to);
       ImGui::SameLine();
@@ -387,6 +375,7 @@ void update_and_render(Arena *arena, App_State &app, f32 delta_time_ms)
         i64 cluster_to_highlight = app.viewer.highlighted_cluster;
         ImGui::PushItemWidth(100.f);
         if (ImGui::InputScalar("##highlighted_cluster", ImGuiDataType_S64, &cluster_to_highlight, &step_i64, &step_fast_i64, "%u")) {
+          app.viewer.highlight_cluster = true;
           viewer_jump_to_cluster(app, cluster_to_highlight);
         }
         ImGui::PopItemWidth();
diff --git a/src/render.h b/src/render.h
index 2cac229..57421b6 100644
--- a/src/render.h
+++ b/src/render.h
@@ -1,20 +1,11 @@
 struct Viewer {
   MemoryEditor mem_edit;
   
-  f32 col_anchor[3];
-  f32 col_header[3];
-  f32 col_footer[3];
+  f32 col_section[Sec_COUNT][3];
   f32 col_key[3];
-  f32 col_tfile_header[3];
-  f32 col_tfile_obj[3];
-  f32 col_tfile_info[3];
-  f32 col_tfile_free[3];
-  f32 col_page[3];
-  f32 col_page_start[3];
   f32 col_checksum[3];
-  f32 col_page_list[3];
-  f32 col_tkeys_list[3];
   f32 col_highlight[3];
+  f32 col_page_start[3];
 
   u64 base_display_addr;
   
diff --git a/src/rntuple.h b/src/rntuple.h
index adcaf8a..fd0362b 100644
--- a/src/rntuple.h
+++ b/src/rntuple.h
@@ -84,3 +84,42 @@ struct RNTuple_Data {
   Page_Info_Chunk *page_chunks;
   u64 n_page_chunks;
 };
+
+// A Section represents an interesting sequence of bytes in the file.
+// It is associated to stuff such as a color, some metadata, etc.
+enum Section_Id {
+  Sec_None,
+  Sec_TFile_Header,
+  Sec_TFile_Object,
+  Sec_TFile_Info,
+  Sec_TFile_FreeList,
+  Sec_TKey_List,
+  Sec_RNTuple_Anchor,
+  Sec_RNTuple_Header,
+  Sec_RNTuple_Footer,
+  Sec_Page,
+  Sec_Page_List,
+
+  Sec_COUNT
+};
+
+struct Section {
+  Section_Id id;
+  Byte_Range range;
+  u64 post_size; // usually the checksum, included in `range`
+  b8 highlighted;
+};
+
+inline const String8 section_names[Sec_COUNT] = {
+  str8("None"),
+  str8("TFile Header"),
+  str8("TFile Object"),
+  str8("TFile Info"),
+  str8("TFile FreeList"),
+  str8("TKey List"),
+  str8("RNTuple Anchor"),
+  str8("RNTuple Header"),
+  str8("RNTuple Footer"),
+  str8("Page"),
+  str8("Page List"),
+};