[1.2-r1219] Center pane of BorderLayout obscured by blue box

[RFtwatkins]

Sample code:
http://www.extpaste.com/#2093

There is an infrequent, but seemingly impossible to get rid of box that conceals the central pane of a border panel.
it will show up if you set center.getState().put("collapsed", true);
But otherwise it only seems to come up infrequently.

note: I have put center.getState().remove("collapsed"); in several parts of my code and can get it less frequent, but it never goes away for good. I set collapsed to true on east, west, and south, but never on center. I have tried getting rid of all collapsed=true, but then the panes on the other tabs do not collapse when instructed.

More recently I added a border layout to the South pane, and now the South pane will have the concealing box on occasion as well(in its own center pane of course)

The display hierarchy to the problem layouts is:
Viewport(RowLayout(Vertical))
>ContentPanel(RowLayout(Vertical))
->TabPanel
-->TabItem(RowLayout(Vertical))
--->LayoutContainer(BorderLayout) (South, Center, East, West)
---->[center]ContentPanel(RowLayout(Vertical)) <--- problem happens here
---->[South]ContentPanel(FitLayout)
----->LayoutContainer(BorderLayout)(Center, East)
------>[center]ContentPanel(FitLayout) <--- problem happens here too

Thanks for your time,
Travis

Note: Still happening in GXT 1.2.4 on GWT 1.5.3