Possible to make the title of an 'AVH Extended Categories' widget clickable?

I have a couple of AVH Extended Categories widgets in my left sidebar.

One of those widgets, for example looks like this:

DESIGN
– Web Design
– Graphic Design
– User Experience Design

Here, ‘DESIGN’ is the unclickable title of the widget, while ‘Web Design’, ‘Graphic Design’ and ‘User Experience Design’ are the clickable categories listed below the title.

For example, by clicking ‘Graphic Design’, the user gets directed to a page where only blogposts belonging to the category ‘Graphic Design’ are shown.

What I’m trying to achieve is to make the unclickable title of the widget (‘DESIGN’) clickable so that when one clicks on it, all posts from the categories that belong to ‘DESIGN’ are shown, so all posts from ‘Web Design’, ‘Graphic Design’ and ‘User Experience Design’ should all be shown.

Is it possible to realize that using the standard settings? If not, is it possible to somehow edit the code to make that possible?

https://wordpress.org/plugins/extended-categories-widget/

Edit: I know that it is possible to realize this using the main menu of the website, but I need to achieve this effect in the sidebar as well.

Edit 2: I already have a category named ‘Design’ which is the parent category of the three other subcategories.