Major Description
The problem was discovered during the development of a reusable CollapsableBorder component.
The component is intended to be used to create collapsable sections on web pages (clicking a link collapses/expands the section, i.e. the border contents).
The component works as expected, unless CollapsableBorders are nested inside each other. In such cases collapsing an inner border, followed by a collapse and expand operation on the outer border produces an exception.
The problem is described in greater detail in the following thread from the mailing list:
http://www.nabble.com/Problems-toggling-visibility-on-nested-borders-td17528668.html