Tab and backtab (shift-tab) functions are enabled to facilitate navigating through the cells. These functions are active whenever the editable attribute is set to true. As the editable attribute is set either for the entire container details part, or on a column-by-column basis, the tab/backtab function responds according to context. You can try out the tab and backtab (shift-tab) functions on any of the parts in the sample application except for the AbtContainerColumnsProportionalResizingExampleView. This latter view has the editable attribute set to false.