Resizing with sizePane yields wrong animation in jquery-ui-layout

Question

I have two nested layouts the mainLayout and the westlayout which looks like this:

 ____________________________
|        |                  |          
|        |                  |          
|  W-C   |                  |
|        |        C         |
|________|                  |
|        |                  |
|  W-S   |                  |
|________|__________________|

The Main layout consists of two panes (West and Center). The westlayout also consists of two panes (Center and South).

Now i added a custom toggler to the west pane of the mainLayout which does mainLayout.sizePane("west", x) where x can be 40 or 300 depending on the state of the pane.

The initial state is all panels open up like this:

When i click the toggler the first time, the complete west Pane will animate to 40px width which works correct. The state looks now like this:

Now if i click the toggler again the pain is supposed to go back to its initial (300px) width. Again i'm only using sizePane("west", 300) on the main Layout. This will basicly work, but during the animation from the 40px state to the 300px state for some reason only the west-south pane is animated and the west-center pane "pops" back to 300px after the west-south pane has finished animating.

During the animation it looks like this:

The layoutOptions for the panes are prettymuch the default. Here are the differences from the default (every pane has the same):

{
            paneSelector                : '.' + $container.attr('class'),
            minSize                     : (subRegion.minSize>0) ? subRegion.minSize : 0,
            size                        : (subRegion.size>=0) ? subRegion.size : "auto",
            initHidden                  : subRegion.hidden,

            fxSpeed                     : 200,
            animatePaneSizing           : true,
            spacing_open                : 3,
            spacing_closed              : 3,
            triggerEventsDuringLiveResize : true,
            resizerDblClickToggle: false,
            onresize                    : onResize,
}

• Is there something i have to note when using sizePane with nested layouts ?
• Am i missing any call to child layouts or something?