JXStatusBar is blowing up parent containers. It needs a minimum width of 0.
A JXLabel or JLabel has a preferred size which is the render size of its text.
JXStatusBar has a LayoutManager in BasicStatusBarUI which uses the preferred
size as the minimum size.
If you put a JXLabel into a JXStatusBar, then the JXStatusBar minimum size is
then the size of the text.
This blows the enclosing window out of proportion.
If you override getMinimumSize() in JXStatusBar to return a 0 width, with the
preferred height, then all behaves correctly.
Proper fix: The LayoutManager in BasicStatusBarUI should return 0 width (and
possibly height) from minimumSize().