diff --git a/app-proto/src/display.rs b/app-proto/src/display.rs
index 494dd3c..c39e575 100644
--- a/app-proto/src/display.rs
+++ b/app-proto/src/display.rs
@@ -506,20 +506,7 @@ pub fn Display() -> View {
                 
                 // if we clicked something, select it
                 match clicked {
-                    Some((key, _)) => {
-                        if event.shift_key() {
-                            state.selection.update(|sel| {
-                                if !sel.remove(&key) {
-                                    sel.insert(key);
-                                }
-                            })
-                        } else {
-                            state.selection.update(|sel| {
-                                sel.clear();
-                                sel.insert(key);
-                            })
-                        }
-                    },
+                    Some((key, _)) => state.select(key, event.shift_key()),
                     None => state.selection.update(|sel| sel.clear())
                 };
             }
diff --git a/app-proto/src/main.rs b/app-proto/src/main.rs
index 897f9d4..8a012d3 100644
--- a/app-proto/src/main.rs
+++ b/app-proto/src/main.rs
@@ -25,6 +25,24 @@ impl AppState {
             selection: create_signal(FxHashSet::default())
         }
     }
+    
+    // in single-selection mode, select the element with the given key. in
+    // multiple-selection mode, toggle whether the element with the given key
+    // is selected
+    fn select(&self, key: ElementKey, multi: bool) {
+        if multi {
+            self.selection.update(|sel| {
+                if !sel.remove(&key) {
+                    sel.insert(key);
+                }
+            });
+        } else {
+            self.selection.update(|sel| {
+                sel.clear();
+                sel.insert(key);
+            });
+        }
+    }
 }
 
 fn main() {
diff --git a/app-proto/src/outline.rs b/app-proto/src/outline.rs
index e2cf49c..148f870 100644
--- a/app-proto/src/outline.rs
+++ b/app-proto/src/outline.rs
@@ -83,18 +83,7 @@ fn ElementOutlineItem(key: ElementKey, element: assembly::Element) -> View {
                         move |event: KeyboardEvent| {
                             match event.key().as_str() {
                                 "Enter" => {
-                                    if event.shift_key() {
-                                        state.selection.update(|sel| {
-                                            if !sel.remove(&key) {
-                                                sel.insert(key);
-                                            }
-                                        });
-                                    } else {
-                                        state.selection.update(|sel| {
-                                            sel.clear();
-                                            sel.insert(key);
-                                        });
-                                    }
+                                    state.select(key, event.shift_key());
                                     event.prevent_default();
                                 },
                                 "ArrowRight" if constrained.get() => {