Can I modify a text box defined as Web Type CCM_EXTENDED_TEXT attribute to have its size default to the size of the text it contains?
The default size of the text box containing CCM_EXTENDED_TEXT is define in the process package's XML file. Its value is a constant that does not dynamically adjust.
Unfortunately, there is no way provided to have the size of the CCM_EXTENDED_TEXT box automatically expand to the exact size of a text field.
However, it is possible to govern the size of the box by editing the 'Define Dialog' for the lifecycle or 'Show' dialog for a given state, select the desired attribute having Web type CCM_EXTENDED_TEXT, and increase the height by a set number of rows. If it is consistently too small, you can adjust this to a default value that provides a larger size for the field. It may take a few iterations to find a setting that meets your needs.
After changing the default size, the size can still be increased as needed when viewing a CR.