Rework MenuBar. Add MenuButton. Add mouse event cascading to floaters.
LinearLayout: spacing now applies to all children, not just those with expand.
Fix Window resize request inside layouts.
UnicodeGraphics: prepare for styling/theming.
Button
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.. toctree::
:maxdepth: 3
:titlesonly:
.. automodule:: tuikit.button
:members:
:show-inheritance: