How can I add my own button to textarea

how can I add my own button to the standard textarea?
I need a center- button.

What have I to do to extend a coreplugin in K3?


Not particularly a button, but that should do the trick:

a center KT to develop is not the problem.
I have written my own kirbytag but what I need is a Button in the toolbar for my customer.
But thanks for the link.


You might be able to find a starting point by looking at existing field extensions, for example: