drawing decoration on top of TextView

[Kasper Peeters <kasper peeters aei mpg de>]

Dear all,

I would like to draw some decoration in the border region of a Container
widget. What is the recommended way to do this? 

(To be more specific: I have a bunch of TextView objects above each
other, and want to draw a little

     __
     |
     |
     |
     --

type 'bracket' which shows the size of each of them. Without such a
bracket it is impossible to see where one TextView starts and the next
one ends. A themeable solution would be preferred).

Best,
Kasper