ULAYERS opens in a drawing without underlays; the ribbon runs ULAYERS

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/app/commands/display.rs

@@ -2051,7 +2051,7 @@ impl OpenCADStudio {
                 }
             }
 
-            "UNDERLAYLAYERS" | "ULAYERS" => self.open_underlay_layers_dialog(i),
+            "ULAYERS" => self.open_underlay_layers_dialog(i),
             "RECAP" | "SYNCPVIEWPORTS" => {
                 self.command_line
                     .push_info(crate::tf!("{cmd}: not yet implemented.").as_ref());

src/app/commands/pdf_dialogs.rs

@@ -289,7 +289,8 @@ impl OpenCADStudio {
         }
     }
 
-    /// ULAYERS: every underlay of the drawing, the selected one first shown.
+    /// ULAYERS: every underlay of the drawing, the selected one first shown
+    /// (none: an empty dialog).
     pub(in crate::app) fn open_underlay_layers_dialog(&mut self, i: usize) {
         let document = &self.tabs[i].scene.document;
         let selected: Vec<codec::Handle> = self.tabs[i]
@@ -329,10 +330,6 @@ impl OpenCADStudio {
                 hidden: crate::scene::model::pdf_layers::hidden_layers(u),
             });
         }
-        if targets.is_empty() {
-            self.command_line.push_error("No underlays found.");
-            return;
-        }
         let current = targets
             .iter()
             .position(|t| selected.contains(&t.handle))