diff --git a/src/Gui/DlgParameterImp.cpp b/src/Gui/DlgParameterImp.cpp
index 8e8752b406..02deea24ac 100644
--- a/src/Gui/DlgParameterImp.cpp
+++ b/src/Gui/DlgParameterImp.cpp
@@ -483,7 +483,7 @@ ParameterGroup::~ParameterGroup()
 void ParameterGroup::contextMenuEvent ( QContextMenuEvent* event )
 {
     QTreeWidgetItem* item = currentItem();
-    if (item->isSelected())
+    if (item && item->isSelected())
     {
         expandAct->setEnabled(item->childCount() > 0);
         // do not allow to import parameters from a non-empty parameter group
@@ -513,7 +513,7 @@ void ParameterGroup::keyPressEvent (QKeyEvent* event)
 void ParameterGroup::onDeleteSelectedItem()
 {
     QTreeWidgetItem* sel = currentItem();
-    if (sel->isSelected() && sel->parent())
+    if (sel && sel->isSelected() && sel->parent())
     {
         if ( QMessageBox::question(this, tr("Remove group"), tr("Do you really want to remove this parameter group?"),
                                QMessageBox::Yes, QMessageBox::No|QMessageBox::Default|QMessageBox::Escape) == 
@@ -537,7 +537,7 @@ void ParameterGroup::onDeleteSelectedItem()
 void ParameterGroup::onToggleSelectedItem()
 {
     QTreeWidgetItem* sel = currentItem();
-    if (sel->isSelected())
+    if (sel && sel->isSelected())
     {
         if (sel->isExpanded())
             sel->setExpanded(false);
@@ -555,7 +555,7 @@ void ParameterGroup::onCreateSubgroup()
     if (ok && Gui::validateInput(this, name))
     {
         QTreeWidgetItem* item = currentItem();
-        if (item->isSelected())
+        if (item && item->isSelected())
         {
             ParameterGroupItem* para = static_cast<ParameterGroupItem*>(item);
             Base::Reference<ParameterGrp> hGrp = para->_hcGrp;
@@ -581,7 +581,7 @@ void ParameterGroup::onExportToFile()
     if ( !file.isEmpty() )
     {
         QTreeWidgetItem* item = currentItem();
-        if (item->isSelected())
+        if (item && item->isSelected())
         {
             ParameterGroupItem* para = static_cast<ParameterGroupItem*>(item);
             Base::Reference<ParameterGrp> hGrp = para->_hcGrp;
@@ -597,7 +597,7 @@ void ParameterGroup::onImportFromFile()
     if ( !file.isEmpty() )
     {
         QTreeWidgetItem* item = currentItem();
-        if (item->isSelected())
+        if (item && item->isSelected())
         {
             ParameterGroupItem* para = static_cast<ParameterGroupItem*>(item);
             Base::Reference<ParameterGrp> hGrp = para->_hcGrp;
@@ -631,7 +631,7 @@ void ParameterGroup::onImportFromFile()
 void ParameterGroup::onRenameSelectedItem()
 {
     QTreeWidgetItem* sel = currentItem();
-    if (sel->isSelected())
+    if (sel && sel->isSelected())
     {
         editItem(sel, 0);
     }
@@ -750,7 +750,7 @@ void ParameterValue::onChangeSelectedItem()
 void ParameterValue::onDeleteSelectedItem()
 {
     QTreeWidgetItem* sel = currentItem();
-    if (sel->isSelected())
+    if (sel && sel->isSelected())
     {
         takeTopLevelItem(indexOfTopLevelItem(sel));
         static_cast<ParameterValueItem*>(sel)->removeFromGroup();
@@ -761,7 +761,7 @@ void ParameterValue::onDeleteSelectedItem()
 void ParameterValue::onRenameSelectedItem()
 {
     QTreeWidgetItem* sel = currentItem();
-    if (sel->isSelected())
+    if (sel && sel->isSelected())
     {
         editItem(sel, 0);
     }