I don’t know what the this.properties.nodeMinWidth is in your code, so I guessed various values such as 50 or 70.
Because the TextBlock in each TableRow Panel stretches horizontally, it does not impose any minimum width on the TableRow Panel or on the Table Panel whose itemArray is data bound.
That means it’s the headerPanel that determines the minimum width. So its TextBlock (which is bound to the node’s data.nnm property) is what determines the width of the “NODE” Panel (the resizeObject) when you set that “NODE” Panel’s width to NaN.