vertical (left/right) tabbox content sizing issue

when using a vertical tabbox orient="left/right" the tabpanel doesn't resize properly based on the content.

this works when using a horizontal tabbox.

the attached example reproduces the problem, and contains a partial workaround to make at least the content initially visible when a longer tabpanel is chosen

steps to reproduce

1. run the attached zul
2. in the left-most tabbox, click tab even longer
3. click "Tab short" back

result

tabpanel height doesn't shrink back upon its content