fix_checkboxes_gtk+.diff

diff --git a/src/providers/postgres/qgspgsourceselect.cpp b/src/providers/postgres/qgspgsourceselect.cpp
index 773bb86..678a529 100644
--- a/src/providers/postgres/qgspgsourceselect.cpp
+++ b/src/providers/postgres/qgspgsourceselect.cpp
@@ -76,6 +76,8 @@ QWidget *QgsPgSourceSelectDelegate::createEditor( QWidget *parent, const QStyleO
     if ( values.size() > 0 )
     {
       QComboBox *cb = new QComboBox( parent );
+      ComboBoxItemDelegate* cbid = new ComboBoxItemDelegate();
+      cb->setItemDelegate( cbid );
 
       QStandardItemModel *model = new QStandardItemModel( values.size(), 1, cb );
 
@@ -84,11 +86,9 @@ QWidget *QgsPgSourceSelectDelegate::createEditor( QWidget *parent, const QStyleO
       {
         QStandardItem *item = new QStandardItem( value );
         item->setFlags( Qt::ItemIsUserCheckable | Qt::ItemIsEnabled );
-        item->setCheckable( true );
         item->setData( Qt::Unchecked, Qt::CheckStateRole );
         model->setItem( row++, 0, item );
       }
-
       cb->setModel( model );
 
       return cb;
@@ -646,3 +646,24 @@ void QgsPgSourceSelect::setSearchExpression( const QString& regexp )
 {
   Q_UNUSED( regexp );
 }
+
+/** Used to solve the issue with GTK+ and Cleanlooks style.
+ *  In these styles the checkboes are not displayed
+ */
+
+QWidget* ComboBoxItemDelegate::createEditor( QWidget* parent, const QStyleOptionViewItem& option, const QModelIndex& index ) const
+{
+  return QStyledItemDelegate::createEditor( parent, option, index );
+}
+
+
+void ComboBoxItemDelegate::setEditorData( QWidget* editor, const QModelIndex& index ) const
+{
+  QStyledItemDelegate::setEditorData( editor, index );
+}
+
+
+void ComboBoxItemDelegate::setModelData( QWidget* editor, QAbstractItemModel* model, const QModelIndex& index ) const
+{
+  QStyledItemDelegate::setModelData( editor, model, index );
+}
diff --git a/src/providers/postgres/qgspgsourceselect.h b/src/providers/postgres/qgspgsourceselect.h
index 0b5c9bf..218934e 100644
--- a/src/providers/postgres/qgspgsourceselect.h
+++ b/src/providers/postgres/qgspgsourceselect.h
@@ -27,6 +27,7 @@
 #include <QPair>
 #include <QIcon>
 #include <QItemDelegate>
+#include <QStyledItemDelegate>
 
 class QPushButton;
 class QStringList;
@@ -39,7 +40,7 @@ class QgsPgSourceSelectDelegate : public QItemDelegate
     Q_OBJECT;
 
   public:
-    QgsPgSourceSelectDelegate( QObject *parent = NULL )
+    QgsPgSourceSelectDelegate( QObject* parent = NULL )
         : QItemDelegate( parent )
     {}
 
@@ -49,6 +50,21 @@ class QgsPgSourceSelectDelegate : public QItemDelegate
 };
 
 
+class ComboBoxItemDelegate : public QStyledItemDelegate
+{
+    Q_OBJECT;
+
+  public:
+    ComboBoxItemDelegate( QObject* parent = NULL )
+        : QStyledItemDelegate( parent )
+    {}
+
+    QWidget* createEditor( QWidget* parent, const QStyleOptionViewItem& option, const QModelIndex& index ) const override;
+    void setEditorData( QWidget* editor, const QModelIndex& index ) const override;
+    void setModelData( QWidget* editor, QAbstractItemModel* model, const QModelIndex& index ) const override;
+};
+
+
 /** \class QgsPgSourceSelect
  * \brief Dialog to create connections and add tables from PostgresQL.
  *