Optimization of https://github.com/longbridgeapp/gpui-component/pull/329
The issue with the initial width of the Panel has been optimised to
ensure that the left side of a Panel combination like [Some(px(510.)),
None] is initially rendered with a width of 510px.
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Co-authored-by: Jason Lee <huacnlee@gmail.com>
The essence of the problem is that flex_basis initial_size and
flex_basis size are in conflict: the size overwrites the initial_size
percentage and loses the original percentage in extremely narrow parent
groups, so we have to add the field to the state persisting the desired
percentage.
Fix#262

- Export add_panel_at method for TabPanel to split_panel.
- Fix resizeable_panel init size support.
- Fix panel resize to let panel that have initial size will not auto resize on window resize.
- Fix resize_handle sometimes will invisibly bug.
- Update TabPanel new to support give parent StackPanel.