You can find it in "Tags/Matrix binded to formTable". Open an example (dbl click on it), build it ("Build" button below the code) and press dump button (below the table).
In the dump listner I update every matrix value with random number. On my PC (Dual Core E6700@3.2GHz, 8Gb Ram) it has a delay for about one second before table is updated after the first click. Later clicks update table little bit faster.
On my boss's PC there's almost no delay.
The matrix is just a
List<java.util.List<Data>> datas;. Each element is special Data class, you can examine it in the "Code" tab. It has "value" property.