TODO controls

box (base, extensible)
scrollbox box
button
checkbox
column ( vbox )
row ( hbox )
container
image
- event listeners
  - click event
  - mouse move event
progress_bar
radio - [ ] event listener - [ ] on input
scrollbars
slider
- event listener
  - on input
text
text_input (textbox) - [ ] event listener - [x] on input
text_area
- scrollbar dynamic to the relative content size
- scrollbar can be dragged
- scrollbar moves relative to the scroll location
- event listener
  - on input
  - on scroll event
groupbox
- ganged radio button in the same group
combobox, dropdown box
process the key modifiers in events
Fix a bug in inner buffer of flexbox, 1-line off
Charts
- bar charts
- line chart
  - vertical
  - horizontal
- scatter point charts
All widget will have to be wrapped with Rc<Mutex<_>> in order for it to have multiple owner that can modify the UI

Document