Cleanup warnings and visual

src/collection_list.rs

@@ -8,14 +8,6 @@ pub struct CollectionListItem {
     name: String,
 }
 
-impl CollectionListItem {
-    pub fn new(name: String) -> Self {
-        Self {
-            name,
-        }
-    }
-}
-
 #[relm4::factory(pub)]
 impl FactoryComponent for CollectionListItem {
     type Init = String;

src/main.rs

@@ -62,6 +62,7 @@ impl SimpleComponent for AppModel {
                             append_column = &gtk::ColumnViewColumn {
                                 set_title: Some("Name"),
                                 set_resizable: true,
+                                set_expand: true,
                                 set_factory:  Some(&factory1)
                             },
                             append_column = &gtk::ColumnViewColumn {