Most of the built in controls have parameters, which
  allow some basic customization. 
    - Open the <web-extension>\share-config-custom.xml file.
 - 
        Change the number of rows and columns used for the
        textarea control that the
        cm:description field uses by default.
        
<config evaluator="node-type" condition="cm:content"> <forms> <form> <appearance> <field id="cm:description"> <control> <control-param name="rows">20</control-param> <control-param name="columns">80</control-param> </control> </field> </appearance> </form> </forms> </config> - 
        If all textarea controls in the application need
        to have these settings, configure the control in the
        default-controls element. For example:
        
<config evaluator="node-type" condition="cm:content"> <forms> <default-controls> <type name="d:mltext"> <control-param name="rows">20</control-param> <control-param name="columns">80</control-param> </type> </default-controls> </forms> </config> - Save the file.