Do not replace textbox in Find/Replace dialog if no text is selected

See #2070

Author: fulvioieva

app/src/processing/app/Editor.java

@@ -1236,6 +1236,7 @@ public void actionPerformed(ActionEvent e) {
           if (find == null) {
             find = new FindReplace(Editor.this);
           }
+          if (getSelectedText()!= null) find.setFindText( getSelectedText() );
           //new FindReplace(Editor.this).show();
           find.setVisible(true);
           //find.setVisible(true);