fix #7698 Fix class cast exception
ref #7010 Adapt datasource handlers for multiple selection
Fix canExecute() check for data source update handler
ref #6912 Update view when creating a new data base model
ref #6912 Use e4 UISynchronize for UI refresh
avoid widgetIsDisposed exceptions by check of control is disposed
ref #6622, #6598 Migrate New and connect menus
ref #6912 Disable multi-select and re-order context menu
fix #6912 Migrate DataSource view