diff --git a/src/canvas.rs b/src/canvas.rs
index 097cf4c..c5c4423 100644
--- a/src/canvas.rs
+++ b/src/canvas.rs
@@ -37,6 +37,7 @@ impl CanvasElement {
 }
 
 // O(1) complexity
+// TODO: This is only a toy implementation, this is not at all correct!
 fn segment_intersects_rect(segment: &druid::kurbo::PathSeg, rect: druid::Rect) -> bool {
     match segment {
         druid::kurbo::PathSeg::Line(line) => rect.contains(line.p0) || rect.contains(line.p1),
@@ -46,7 +47,7 @@ fn segment_intersects_rect(segment: &druid::kurbo::PathSeg, rect: druid::Rect) -
         }
 
         druid::kurbo::PathSeg::Cubic(cubic) => {
-            rect.contains(cubic.p0) || rect.contains(cubic.p1) || rect.contains(cubic.p2)
+            rect.contains(cubic.p0) || rect.contains(cubic.p1) || rect.contains(cubic.p2) || rect.contains(cubic.p3)
         }
     }
 }
@@ -68,6 +69,7 @@ impl Canvas {
     pub fn erase(&mut self, eraser_rect: druid::Rect) {
         for elem in self.elements.iter_mut() {
             if elem.bounding_box().intersect(eraser_rect).area() > 0.0 {
+                // TODO: if a part of the path is erased, split the path into subpaths
                 match elem {
                     CanvasElement::Freehand { path, thickness: _ } => {
                         // Remove segments intersecting the eraser
@@ -82,7 +84,7 @@ impl Canvas {
         }
     }
 
-    pub fn push_back(&mut self, element: CanvasElement) {
+    pub fn add_element(&mut self, element: CanvasElement) {
         self.elements.push_back(element);
     }
 }
diff --git a/src/canvas_tools.rs b/src/canvas_tools.rs
index ba26292..5b4fca3 100644
--- a/src/canvas_tools.rs
+++ b/src/canvas_tools.rs
@@ -67,7 +67,7 @@ impl CanvasTool {
                     if let Some(current_element) = current_element.take() {
                         canvas.update(move |canvas: &Canvas| -> Canvas {
                             let mut new_canvas = canvas.clone();
-                            new_canvas.push_back(current_element);
+                            new_canvas.add_element(current_element);
                             return new_canvas;
                         });
                     }