Problem deleting tabs

I have seen something that I believe is a bug.

I have a form containing two tabPanels. One is used to show each for a user opens and the other one is used to show the labels for the tabs, with a better appearance and an image with a cross to close the tab.

If the tabPanel that contains the forms has the property tabOrientation set to HIDE and I remove one tab the forms are mixed, I mean clicking on another tab shows the wrong form. The strange thing is that setting the tabOrientation to TOP works perfectly.

Is that a bug?

Thanks in advance.

Do you have a sample for this behavior?

I will create a sample solution.