Update current item in generic wxDataViewCtrl::SetSelections()

SetSelections was clearing the previous selection, invalidating the
current item, but didn't set it after selecting the new items.

This was causing issues in keyboard selection, e.g. pressing Shift+click
didn't select all the items between the selected and the clicked ones.

Fix this by making the last item of the new selection current, which is
the expected behaviour considering that SetSelections() should be
equivalent to calling SetSelection() with all items one by one.

Signed-off-by: Anil Kumar <anilkumar8753@gmail.com>

Closes https://github.com/wxWidgets/wxWidgets/pull/557

src/generic/datavgen.cpp

@@ -5414,6 +5414,9 @@ void wxDataViewCtrl::SetSelections( const wxDataViewItemArray & sel )
 {
     m_clientArea->ClearSelection();
 
+    if ( sel.empty() )
+        return;
+
     wxDataViewItem last_parent;
 
     for ( size_t i = 0; i < sel.size(); i++ )
@@ -5431,6 +5434,9 @@ void wxDataViewCtrl::SetSelections( const wxDataViewItemArray & sel )
         if( row >= 0 )
             m_clientArea->SelectRow(static_cast<unsigned int>(row), true);
     }
+
+    // Also make the last item as current item
+    DoSetCurrentItem(sel.Last());
 }
 
 void wxDataViewCtrl::Select( const wxDataViewItem & item )