diff --git a/libavogadro/src/extensions/insertfragmentdialog.cpp b/libavogadro/src/extensions/insertfragmentdialog.cpp
index a0ef8e560..31058b4fb 100644
--- a/libavogadro/src/extensions/insertfragmentdialog.cpp
+++ b/libavogadro/src/extensions/insertfragmentdialog.cpp
@@ -89,12 +89,25 @@ namespace Avogadro {
     // Mac and Windows use relative path from application location
     m_directory = QCoreApplication::applicationDirPath() + "/../share/avogadro/";
 #endif
-    m_directory += directory; // fragments or crystals
+    m_directory += directory; // fragments or crystals or whatever
     if ( directory.contains(QLatin1String("crystals")) )
       d->crystalFiles = true;
     else
       d->crystalFiles = false;
 
+    QDir dir(m_directory);
+    if (!dir.exists() || !dir.isReadable() ) {
+      qWarning() << "Cannot find the directory: " << m_directory;
+
+      // Can't really do anything!
+      ui.directoryTreeView->setEnabled(false);
+      ui.insertFragmentButton->setEnabled(false);
+      ui.filterLineEdit->setEnabled(false);
+      ui.clearToolButton->setEnabled(false);
+
+      return;
+    }
+
     d->model = new QFileSystemModel(this);
     d->model->setReadOnly(true);
     QModelIndex rootIndex = d->model->setRootPath(m_directory);
@@ -141,8 +154,6 @@ namespace Avogadro {
 
   const Molecule &InsertFragmentDialog::fragment()
   {
-    OBMol obfragment;
-
     // The selected model index is in the proxy
     QModelIndexList selected = ui.directoryTreeView->selectionModel()->selectedIndexes();
 
diff --git a/libavogadro/src/extensions/insertfragmentextension.cpp b/libavogadro/src/extensions/insertfragmentextension.cpp
index 48b5075fe..fe9f59923 100644
--- a/libavogadro/src/extensions/insertfragmentextension.cpp
+++ b/libavogadro/src/extensions/insertfragmentextension.cpp
@@ -34,6 +34,7 @@
 
 #include <QInputDialog>
 #include <QDebug>
+#include <QTimer>
 
 using namespace std;
 using namespace OpenBabel;
@@ -51,7 +52,8 @@ namespace Avogadro {
     Extension(parent),
     m_fragmentDialog(0),
     m_crystalDialog(0),
-    m_molecule(0)
+    m_molecule(0),
+    m_justFinished(false)
   {
     QAction *action = new QAction(this);
     action->setText(tr("Crystal..."));
@@ -230,15 +232,18 @@ namespace Avogadro {
               }
             }
           }
-        if (noSelectedHatoms) // add the heavy atom
+        if (noSelectedHatoms && !selectedIds.contains(atom->id())) { // add the heavy atom
           selectedIds.append(atom->id());
+        }
 
-      } else {
+      } else { // this is a hydrogen
         const Atom *hydrogen = atom;
-        if (!hydrogen->neighbors().empty()) {
+        if (!hydrogen->neighbors().empty()) { // it's bonded to something
           atom = m_molecule->atomById(hydrogen->neighbors()[0]); // the first bonded atom to this "H"
         }
-        selectedIds.append(atom->id());
+        if (!selectedIds.contains(atom->id())) {
+          selectedIds.append(atom->id());
+        }
       }
     }
 
@@ -251,6 +256,14 @@ namespace Avogadro {
     if (!dialog)
       return;
 
+    // Prevent "double insert"
+    if (m_justFinished)
+      return;
+
+    // Don't allow two inserts unless spaced by 2 seconds
+    // This avoids a "double insert"
+    QTimer::singleShot(2*1000, this, SLOT(resetTimer()));
+
     const Molecule fragment = dialog->fragment();
     if (fragment.numAtoms() == 0)
       return;
@@ -258,6 +271,7 @@ namespace Avogadro {
     *m_molecule = fragment;
     m_molecule->update();
     emit moleculeChanged(m_molecule, Extension::NewWindow);
+    m_justFinished = true;
   }
 
   // only called by the fragment dialog (not SMILES)
@@ -267,6 +281,14 @@ namespace Avogadro {
     if (!dialog)
       return;
 
+    // Prevent "double insert"
+    if (m_justFinished)
+      return;
+
+    // Don't allow two inserts unless spaced by 2 seconds
+    // This avoids a "double insert"
+    QTimer::singleShot(2*1000, this, SLOT(resetTimer()));
+
     // Get the fragment and make sure it exists (e.g., we didn't try to insert a directory
     const Molecule fragment = dialog->fragment();
     if (fragment.numAtoms() == 0)
@@ -287,6 +309,12 @@ namespace Avogadro {
     foreach(int id, selectedIds) {
       emit performCommand(new InsertFragmentCommand(m_molecule, fragment, m_widget, tr("Insert Fragment"), id));
     }
+    m_justFinished = true;
+  }
+
+  void InsertFragmentExtension::resetTimer()
+  {
+    m_justFinished = false; // done with the delay
   }
 
 } // end namespace Avogadro
diff --git a/libavogadro/src/extensions/insertfragmentextension.h b/libavogadro/src/extensions/insertfragmentextension.h
index 1d56fe575..40b30ca34 100644
--- a/libavogadro/src/extensions/insertfragmentextension.h
+++ b/libavogadro/src/extensions/insertfragmentextension.h
@@ -57,6 +57,9 @@ namespace Avogadro {
     void insertCrystal();
     void insertFragment();
 
+    // With the "grow selected atoms," feature, we need a delay timer
+    void resetTimer();
+
   private:
 
     QList<QAction *> m_actions;
@@ -65,6 +68,8 @@ namespace Avogadro {
     InsertFragmentDialog *m_crystalDialog;
     QString   m_smilesString;
     Molecule *m_molecule;
+
+    bool     m_justFinished;
   };
 
   class InsertFragmentExtensionFactory : public QObject, public PluginFactory