Cell attributes and buffered mode

Use the UNBUFFERED mode when setting cell attributes.

Before version 2.20, array cell attributes were synchronized quite often by the runtime system, and this was not very efficient. As a result, there was not much difference between using buffered or unbuffered mode; when changing cell attributes, the result was immediate even in buffered mode.

Starting with version 2.20, it is recommended that you use the UNBUFFERED mode when setting cell attributes; otherwise, the colors will not be synchronized on the front-end.