VERIFIED SOLUTION i

How to resize the preview panel in a Layout Designer Window using a MapBasic (.NET) command

Products affected: MapInfo Pro™, MapInfo Professional®, MapBasic®
At present, you can not resize the preview panel in a Layout Designer Window using a MapBasic® (.NET) command.

This particular functionality has been raised as a product enhancement under the internal reference of MIPRO-93739.
UPDATED:  June 26, 2017