fix(ribbon): load style/layer dropdowns from the document

The Annotate style dropdowns (text / dimension / multileader / table) and
the layer dropdown were hard-coded to "Standard" / "0" and never synced
from the opened document, so they showed placeholder values even with no
file open and stale values after closing one.

- Start the ribbon's style and layer lists empty instead of with a
  placeholder entry.
- Sync the style dropdowns from the document on file open and on tab
  new/switch/close (the layer sync already ran there).
- Guard sync_ribbon_layers / sync_ribbon_styles / sync_ribbon_from_selection
  for the Start (welcome) tab so all three dropdowns stay empty there.
- When a style family is absent (e.g. no table/multileader styles), fall
  back to empty rather than a non-existent "Standard".

Co-Authored-By: Claude Opus 4.8 <[email protected]>

src/app/layers.rs

@@ -19,6 +19,14 @@ impl OpenCADStudio {
 
     pub(super) fn sync_ribbon_layers(&mut self) {
         let i = self.active_tab;
+        // The Start (welcome) tab has no document — leave the layer and
+        // linetype dropdowns empty instead of showing a placeholder "0".
+        if self.tabs[i].is_start {
+            self.ribbon.set_layers(vec![], "");
+            self.ribbon.set_available_linetypes(vec![]);
+            self.sync_ribbon_styles();
+            return;
+        }
         let active = self.tabs[i].active_layer.clone();
         let infos: Vec<crate::ui::ribbon::LayerInfo> = self.tabs[i]
             .layers
@@ -63,6 +71,13 @@ impl OpenCADStudio {
 
     pub(super) fn sync_ribbon_styles(&mut self) {
         let i = self.active_tab;
+        // The Start (welcome) tab has no real document — keep the Annotate
+        // style dropdowns empty rather than showing a placeholder style.
+        if self.tabs[i].is_start {
+            self.ribbon
+                .set_styles(vec![], "", vec![], "", vec![], "", vec![], "");
+            return;
+        }
         let doc = &self.tabs[i].scene.document;
 
         let text_names: Vec<String> = doc.text_styles.iter().map(|s| s.name.clone()).collect();
@@ -73,7 +88,7 @@ impl OpenCADStudio {
             text_names
                 .first()
                 .cloned()
-                .unwrap_or_else(|| "Standard".to_string())
+                .unwrap_or_default()
         };
 
         let dim_names: Vec<String> = doc.dim_styles.iter().map(|s| s.name.clone()).collect();
@@ -84,7 +99,7 @@ impl OpenCADStudio {
             dim_names
                 .first()
                 .cloned()
-                .unwrap_or_else(|| "Standard".to_string())
+                .unwrap_or_default()
         };
 
         let mleader_names: Vec<String> = doc
@@ -105,7 +120,7 @@ impl OpenCADStudio {
             mleader_names
                 .first()
                 .cloned()
-                .unwrap_or_else(|| "Standard".to_string())
+                .unwrap_or_default()
         };
 
         let table_names: Vec<String> = doc
@@ -126,7 +141,7 @@ impl OpenCADStudio {
             table_names
                 .first()
                 .cloned()
-                .unwrap_or_else(|| "Standard".to_string())
+                .unwrap_or_default()
         };
 
         let active_mleader2 = active_mleader.clone();

src/app/properties.rs

@@ -325,6 +325,12 @@ impl OpenCADStudio {
     /// marker to do better).
     pub(super) fn sync_ribbon_from_selection(&mut self) {
         let i = self.active_tab;
+        // The Start (welcome) tab has no document — keep the ribbon's
+        // current-layer chip empty rather than re-seeding it with a default.
+        if self.tabs[i].is_start {
+            self.ribbon.active_layer = String::new();
+            return;
+        }
         let selected = self.tabs[i].scene.selected_entities();
         if selected.is_empty() {
             // Creation defaults: prefer the file's saved CECOLOR / CELTYPE /

src/app/update.rs

@@ -322,6 +322,10 @@ impl OpenCADStudio {
                     .layers
                     .sync_with_viewports(&doc_layers, vp_info);
                 self.sync_ribbon_layers();
+                // Load the Annotate-ribbon style dropdowns (text / dimension /
+                // multileader / table) from the opened document instead of
+                // leaving them on the hard-coded "Standard" default.
+                self.sync_ribbon_styles();
                 // Reset the Home-ribbon Color / Linetype / Lineweight chips
                 // to the newly opened document's CECOLOR / CELTYPE / CELWEIGHT
                 // defaults (or to ByLayer when the file leaves them empty).
@@ -917,6 +921,7 @@ impl OpenCADStudio {
                 self.tabs.push(new_tab);
                 self.active_tab = self.tabs.len() - 1;
                 self.sync_ribbon_layers();
+                self.sync_ribbon_styles();
                 // #21: reset ribbon Color / Linetype / Lineweight to the
                 // fresh tab's defaults (ByLayer) instead of inheriting the
                 // previous tab's last selection.
@@ -928,6 +933,7 @@ impl OpenCADStudio {
                 if idx < self.tabs.len() {
                     self.active_tab = idx;
                     self.sync_ribbon_layers();
+                    self.sync_ribbon_styles();
                     // #21: also re-seed ribbon Color / Linetype / Lineweight
                     // from the newly active tab so they reflect that doc's
                     // CECOLOR / CELTYPE / CELWEIGHT (or its current selection
@@ -963,6 +969,7 @@ impl OpenCADStudio {
                 // different existing tab; in both cases the ribbon needs
                 // to track that doc's defaults / selection. #21.
                 self.sync_ribbon_layers();
+                self.sync_ribbon_styles();
                 self.sync_ribbon_from_selection();
                 Task::none()
             }

src/ui/ribbon/mod.rs

@@ -74,15 +74,10 @@ impl Ribbon {
             ortho_mode: true,
             open_dropdown: None,
             last_cmd: HashMap::default(),
-            layer_names: vec!["0".to_string()],
-            active_layer: "0".to_string(),
-            layer_infos: vec![LayerInfo {
-                name: "0".to_string(),
-                color: Color::WHITE,
-                visible: true,
-                frozen: false,
-                locked: false,
-            }],
+            // Empty until a document is open — populated by sync_ribbon_layers.
+            layer_names: vec![],
+            active_layer: String::new(),
+            layer_infos: vec![],
             active_color: AcadColor::ByLayer,
             active_linetype: "ByLayer".to_string(),
             active_lineweight: LineWeight::ByLayer,
@@ -91,14 +86,16 @@ impl Ribbon {
                 art: String::new(),
             }],
             prop_color_palette_open: false,
-            text_style_names: vec!["Standard".to_string()],
-            active_text_style: "Standard".to_string(),
-            dim_style_names: vec!["Standard".to_string()],
-            active_dim_style: "Standard".to_string(),
-            mleader_style_names: vec!["Standard".to_string()],
-            active_mleader_style: "Standard".to_string(),
-            table_style_names: vec!["Standard".to_string()],
-            active_table_style: "Standard".to_string(),
+            // Empty until a document is open — the Annotate style dropdowns
+            // are populated from the active document by sync_ribbon_styles.
+            text_style_names: vec![],
+            active_text_style: String::new(),
+            dim_style_names: vec![],
+            active_dim_style: String::new(),
+            mleader_style_names: vec![],
+            active_mleader_style: String::new(),
+            table_style_names: vec![],
+            active_table_style: String::new(),
         }
     }