diff --git a/app/src/processing/app/Sketch.java b/app/src/processing/app/Sketch.java
index 8adcb7993..c3d6382f5 100644
--- a/app/src/processing/app/Sketch.java
+++ b/app/src/processing/app/Sketch.java
@@ -39,6 +39,7 @@ import java.awt.event.KeyEvent;
 import java.beans.PropertyChangeEvent;
 import java.beans.PropertyChangeListener;
 import java.io.*;
+import java.util.ArrayList;
 import java.util.List;
 
 import javax.swing.*;
@@ -143,44 +144,19 @@ public class Sketch {
     codeFolder = new File(folder, "code");
     dataFolder = new File(folder, "data");
 
-    // get list of files in the sketch folder
-    String list[] = folder.list();
+    List<String> filenames = new ArrayList<>();
+    List<String> extensions = new ArrayList<>();
 
-    // reset these because load() may be called after an
-    // external editor event. (fix for 0099)
-    codeCount = 0;
+    getSketchCodeFiles(filenames, extensions);
 
-    code = new SketchCode[list.length];
+    codeCount = filenames.size();
+    code = new SketchCode[codeCount];
 
-    String[] extensions = mode.getExtensions();
-
-    for (String filename : list) {
-      // Ignoring the dot prefix files is especially important to avoid files
-      // with the ._ prefix on Mac OS X. (You'll see this with Mac files on
-      // non-HFS drives, i.e. a thumb drive formatted FAT32.)
-      if (filename.startsWith(".")) continue;
-
-      // Don't let some wacko name a directory blah.pde or bling.java.
-      if (new File(folder, filename).isDirectory()) continue;
-
-      // figure out the name without any extension
-      String base = filename;
-      // now strip off the .pde and .java extensions
-      for (String extension : extensions) {
-        if (base.toLowerCase().endsWith("." + extension)) {
-          base = base.substring(0, base.length() - (extension.length() + 1));
-
-          // Don't allow people to use files with invalid names, since on load,
-          // it would be otherwise possible to sneak in nasty filenames. [0116]
-          if (isSanitaryName(base)) {
-            code[codeCount++] =
-              new SketchCode(new File(folder, filename), extension);
-          }
-        }
-      }
+    for (int i = 0; i < codeCount; i++) {
+      String filename = filenames.get(i);
+      String extension = extensions.get(i);
+      code[i] = new SketchCode(new File(folder, filename), extension);
     }
-    // Remove any code that wasn't proper
-    code = (SketchCode[]) PApplet.subset(code, 0, codeCount);
 
     // move the main class to the first tab
     // start at 1, if it's at zero, don't bother
@@ -204,6 +180,39 @@ public class Sketch {
   }
 
 
+  public void getSketchCodeFiles(List<String> outFilenames,
+                                 List<String> outExtensions) {
+    // get list of files in the sketch folder
+    String list[] = folder.list();
+
+    for (String filename : list) {
+      // Ignoring the dot prefix files is especially important to avoid files
+      // with the ._ prefix on Mac OS X. (You'll see this with Mac files on
+      // non-HFS drives, i.e. a thumb drive formatted FAT32.)
+      if (filename.startsWith(".")) continue;
+
+      // Don't let some wacko name a directory blah.pde or bling.java.
+      if (new File(folder, filename).isDirectory()) continue;
+
+      // figure out the name without any extension
+      String base = filename;
+      // now strip off the .pde and .java extensions
+      for (String extension : mode.getExtensions()) {
+        if (base.toLowerCase().endsWith("." + extension)) {
+          base = base.substring(0, base.length() - (extension.length() + 1));
+
+          // Don't allow people to use files with invalid names, since on load,
+          // it would be otherwise possible to sneak in nasty filenames. [0116]
+          if (isSanitaryName(base)) {
+            if (outFilenames != null) outFilenames.add(filename);
+            if (outExtensions != null) outExtensions.add(extension);
+          }
+        }
+      }
+    }
+  }
+
+
   /**
    * Reload the current sketch. Used to update the text area when
    * an external editor is in use.
diff --git a/app/src/processing/app/ui/ChangeDetector.java b/app/src/processing/app/ui/ChangeDetector.java
index 081f42334..866d2ffc4 100644
--- a/app/src/processing/app/ui/ChangeDetector.java
+++ b/app/src/processing/app/ui/ChangeDetector.java
@@ -5,7 +5,6 @@ import java.awt.Frame;
 import java.awt.event.WindowEvent;
 import java.awt.event.WindowFocusListener;
 import java.io.File;
-import java.io.FilenameFilter;
 import java.lang.reflect.InvocationTargetException;
 import java.util.ArrayList;
 import java.util.List;
@@ -79,19 +78,12 @@ public class ChangeDetector implements WindowFocusListener {
 
   private boolean checkFileCount() {
     // check file count first
-    File sketchFolder = sketch.getFolder();
-    File[] sketchFiles = sketchFolder.listFiles(new FilenameFilter() {
-      @Override
-      public boolean accept(File dir, String filename) {
-        for (String ext : editor.getMode().getExtensions()) {
-          if (filename.toLowerCase().endsWith(ext.toLowerCase())) {
-            return true;
-          }
-        }
-        return false;
-      }
-    });
-    int fileCount = sketchFiles.length;
+
+    List<String> filenames = new ArrayList<>();
+
+    sketch.getSketchCodeFiles(filenames, null);
+
+    int fileCount = filenames.size();
 
     // Was considering keeping track of the last "known" number of files
     // (instead of using sketch.getCodeCount() here) in case the user