diff --git a/src/main/java/com/github/creme332/controller/FrameController.java b/src/main/java/com/github/creme332/controller/FrameController.java
index 3e6ecde5..a8ca7027 100644
--- a/src/main/java/com/github/creme332/controller/FrameController.java
+++ b/src/main/java/com/github/creme332/controller/FrameController.java
@@ -9,6 +9,7 @@
 import java.awt.event.ActionEvent;
 import java.beans.PropertyChangeEvent;
 import java.beans.PropertyChangeListener;
+import java.util.List;
 
 import javax.swing.*;
 
@@ -158,7 +159,7 @@ public void actionPerformed(ActionEvent e) {
 
         // Open help center
         rootPane.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW)
-                .put(KeyStroke.getKeyStroke(KeyEvent.VK_H, KeyEvent.ALT_DOWN_MASK), "openHelpCenter");
+                .put(KeyStroke.getKeyStroke(KeyEvent.VK_H, java.awt.event.InputEvent.ALT_DOWN_MASK), "openHelpCenter");
         rootPane.getActionMap().put("openHelpCenter", new AbstractAction() {
             @Override
             public void actionPerformed(ActionEvent e) {
@@ -168,7 +169,8 @@ public void actionPerformed(ActionEvent e) {
 
         // Toggle sidebar visibility
         rootPane.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(
-                KeyStroke.getKeyStroke(KeyEvent.VK_S, KeyEvent.CTRL_DOWN_MASK | KeyEvent.SHIFT_DOWN_MASK),
+                KeyStroke.getKeyStroke(KeyEvent.VK_S,
+                        java.awt.event.InputEvent.CTRL_DOWN_MASK | java.awt.event.InputEvent.SHIFT_DOWN_MASK),
                 "toggleSidebar");
         rootPane.getActionMap().put("toggleSidebar", new AbstractAction() {
             @Override
@@ -241,7 +243,7 @@ private void resizeEverything() {
 
         frame.repaint();
         frame.revalidate();
-        
+
         /**
          * sync toolkit to prevent frame rate issues on linux.
          * 
@@ -251,26 +253,34 @@ private void resizeEverything() {
         Toolkit.getDefaultToolkit().sync();
     }
 
-    public void playStartAnimation() {
-        final long animationDuration = 800; // ms
+    private class Task extends SwingWorker<Void, Integer> {
+        static final long ANIMATION_DURATION = 800; // ms
 
-        Thread th = new Thread() {
-            @Override
-            public void run() {
-                // Display the splash screen for 1 second
-                frame.setMenuBarVisibility(false);
-                frame.showScreen(Screen.SPLASH_SCREEN);
-
-                try {
-                    Thread.sleep(animationDuration);
-                } catch (InterruptedException e) {
-                    e.printStackTrace();
-                    System.exit(0);
-                }
-                frame.showScreen(app.getCurrentScreen());
-            }
-        };
-        th.start();
+        @Override
+        protected Void doInBackground() throws Exception {
+            // Display the splash screen for some time
+            frame.setMenuBarVisibility(false);
+            frame.showScreen(Screen.SPLASH_SCREEN);
+            Thread.sleep(ANIMATION_DURATION);
+            return null;
+        }
+
+        @Override
+        protected void process(List<Integer> chunks) {
+            // do nothing
+        }
+
+        @Override
+        protected void done() {
+            // Close splash screen and proceed to main application
+            frame.showScreen(app.getCurrentScreen());
+        }
+    }
+
+    public void playStartAnimation() {
+        // Perform background loading task
+        Task task = new Task();
+        task.execute();
     }
 
     @Override
diff --git a/src/main/java/com/github/creme332/controller/canvas/CanvasController.java b/src/main/java/com/github/creme332/controller/canvas/CanvasController.java
index eac358a4..7fb9fce0 100644
--- a/src/main/java/com/github/creme332/controller/canvas/CanvasController.java
+++ b/src/main/java/com/github/creme332/controller/canvas/CanvasController.java
@@ -102,15 +102,14 @@ public void mouseReleased(MouseEvent arg0) {
                 ShapeManager manager = model.getShapeManager();
 
                 // check if a shape was being dragged previously
-                if (app.getMode() == Mode.MOVE_CANVAS && model.getSelectedShapeIndex() > -1) {
+                if (app.getMode() == Mode.MOVE_CANVAS &&
+                        model.getSelectedShapeIndex() > -1 &&
+                        manager.getShapePreview() != null) {
                     // edit previous shape with shape preview
-
-                    if (manager.getShapePreview() != null) {
-                        manager.editShape(model.getSelectedShapeIndex(), manager.getShapePreview());
-                        manager.setShapePreview(null);
-                        model.setSelectedShape(-1);
-                        canvas.repaint();
-                    }
+                    manager.editShape(model.getSelectedShapeIndex(), manager.getShapePreview());
+                    manager.setShapePreview(null);
+                    model.setSelectedShape(-1);
+                    canvas.repaint();
                 }
             }
         });
diff --git a/src/main/java/com/github/creme332/model/ShapeWrapper.java b/src/main/java/com/github/creme332/model/ShapeWrapper.java
index a5314a76..526c72ab 100644
--- a/src/main/java/com/github/creme332/model/ShapeWrapper.java
+++ b/src/main/java/com/github/creme332/model/ShapeWrapper.java
@@ -78,7 +78,7 @@ public ShapeWrapper(ShapeWrapper wrapper) {
     }
 
     /**
-     * Finds the center of a given shape.
+     * Finds the center of the shape.
      * 
      * @param shape the shape to find the center of
      * @return a Point2D representing the center of the shape
diff --git a/src/main/java/com/github/creme332/model/TutorialModel.java b/src/main/java/com/github/creme332/model/TutorialModel.java
index eb07a74d..b76f74ac 100644
--- a/src/main/java/com/github/creme332/model/TutorialModel.java
+++ b/src/main/java/com/github/creme332/model/TutorialModel.java
@@ -4,7 +4,7 @@
 import java.util.Set;
 
 /**
- * Information about a particular tutorialdraw.
+ * Information about a particular tutorial.
  */
 public class TutorialModel {
     /**