Variable background mask in a Multi-view Block tag

[Gepaha]

The links bellow show  how to create a background mask in a Multi-view Block tag. 

http://architects-desktop.blogspot.com/2019/07/aca-schedule-tag-background-mask.html 

https://knowledge.autodesk.com/support/autocad-architecture/learn-explore/caas/sfdcarticles/sfdcarti... 

It turns out that the mask has a fixed length and does not automatically adjust when text changes. 

Is it possible to create a mask that fits the length of the text? 

Thanks.

[helen.jobe]

In a standard block or annotative block, multiline text attributes can have a background mask that is variable.  After an attribute is created, edit it and click on the "...".  In the text formatting popup box click the down arrow and then choose background mask.

For whatever reason, though, that does not work with multi-view blocks - at least I can't figure out how to do it.

[Gepaha]

Many thanks for the reply.
I have a lot of Mulkti View Block Tags which include information contained in property sets. What I need is that when the content of a property set is changed, the Multi View Block Tag automatically has its mask width adjusted.
I am thinking of implementing this through the use of .NET events. I don't know if that is possible and I haven't had time to pick up on it.
Any help is always welcome in order to have a direction to take.