Does the new Bryntum Gantt has already a plugin such as the TaskArea (or as a standard feature)?
Like the one for ExtGantt: https://www.bryntum.com/blog/writing-a-custom-plugin-for-ext-gantt-3-x/
Support Forum
Nope, there no Task Area plugin. The link you refer to is a blog post that demonstrates how to write a plugin. It is not included in codebase.
I have created feature request here: https://github.com/bryntum/support/issues/209
I have created feature request here: https://github.com/bryntum/support/issues/209