It was still using jdk FileNameExtensionFilter

Author: Federico Fissore

app/src/processing/app/Base.java

@@ -28,12 +28,12 @@
 import java.util.*;
 
 import javax.swing.*;
-import javax.swing.filechooser.FileNameExtensionFilter;
 
 import processing.app.debug.Compiler;
 import processing.app.debug.Target;
 import processing.app.helpers.FileUtils;
 import processing.app.helpers.filefilters.OnlyDirs;
+import processing.app.javax.swing.filechooser.FileNameExtensionFilter;
 import processing.app.tools.ZipDeflater;
 import processing.core.*;
 import static processing.app.I18n._;