DataView/Plot `bgcolor` can't be tuple

[corranwebster]

Problem Description

The when given a bgcolor trait which is a tuple (or other valid non-color name values) DataView code errors with an error like:

Traceback (most recent call last):
  File "/Users/cwebster/src/experiment/chaco/temp/reported_errors.py", line 29, in <module>
    LinePlot().configure_traits()
  File "/Users/cwebster/.venvs/chaco-3.11/lib/python3.11/site-packages/traits/has_traits.py", line 2164, in configure_traits
    rc = toolkit().view_application(
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/cwebster/src/experiment/traitsui/traitsui/qt/toolkit.py", line 237, in view_application
    return view_application.view_application(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/cwebster/src/experiment/traitsui/traitsui/qt/view_application.py", line 92, in view_application
    return ViewApplication(
           ^^^^^^^^^^^^^^^^
  File "/Users/cwebster/src/experiment/traitsui/traitsui/qt/view_application.py", line 127, in __init__
    self.ui = self.view.ui(
              ^^^^^^^^^^^^^
  File "/Users/cwebster/src/experiment/traitsui/traitsui/view.py", line 457, in ui
    ui.ui(parent, kind)
  File "/Users/cwebster/src/experiment/traitsui/traitsui/ui.py", line 234, in ui
    self.rebuild(self, parent)
  File "/Users/cwebster/src/experiment/traitsui/traitsui/qt/toolkit.py", line 168, in ui_live
    ui_live.ui_live(ui, parent)
  File "/Users/cwebster/src/experiment/traitsui/traitsui/qt/ui_live.py", line 52, in ui_live
    _ui_dialog(ui, parent, BaseDialog.NONMODAL)
  File "/Users/cwebster/src/experiment/traitsui/traitsui/qt/ui_live.py", line 72, in _ui_dialog
    BaseDialog.display_ui(ui, parent, style)
  File "/Users/cwebster/src/experiment/traitsui/traitsui/qt/ui_base.py", line 294, in display_ui
    ui.owner.init(ui, parent, style)
  File "/Users/cwebster/src/experiment/traitsui/traitsui/qt/ui_live.py", line 231, in init
    self.add_contents(panel(ui), bbox)
                      ^^^^^^^^^
  File "/Users/cwebster/src/experiment/traitsui/traitsui/qt/ui_panel.py", line 270, in panel
    panel = _GroupPanel(content[0], ui).control
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/cwebster/src/experiment/traitsui/traitsui/qt/ui_panel.py", line 621, in __init__
    layout = self._add_items(content, inner)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/cwebster/src/experiment/traitsui/traitsui/qt/ui_panel.py", line 855, in _add_items
    editor = factory_method(
             ^^^^^^^^^^^^^^^
  File "/Users/cwebster/src/experiment/traitsui/traitsui/editor_factory.py", line 117, in simple_editor
    return self.simple_editor_class(
           ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/cwebster/src/experiment/traitsui/traitsui/editor.py", line 540, in __init__
    self.old_value = getattr(self.object, self.name)
                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/cwebster/src/experiment/chaco/temp/reported_errors.py", line 23, in _plot_default
    plot = Plot(plotdata)
           ^^^^^^^^^^^^^^
  File "/Users/cwebster/src/experiment/chaco/chaco/plot.py", line 198, in __init__
    super().__init__(**kwtraits)
  File "/Users/cwebster/src/experiment/chaco/chaco/data_view.py", line 298, in __init__
    self._init_components()
  File "/Users/cwebster/src/experiment/chaco/chaco/data_view.py", line 361, in _init_components
    if color_table[self.bgcolor] == color_table[grid_color]:
       ~~~~~~~~~~~^^^^^^^^^^^^^^
KeyError: (1.0, 1.0, 0.9)

Proximate cause seems to be code which is trying to ensure that grids can be seen against the background.

Reproduction Steps:

Create a Plot instance with a bgcolor which is a RGB(A) tuple

Plot(bgcolor=(1.0, 1.0, 0.9))

Expected behavior:

Should set the color to the specified tuple.

OS, Python version: All