Dash

Fixed

- [2087](https://github.com/plotly/dash/pull/2087) Fix bug [#2086](https://github.com/plotly/dash/issues/2086) in which using id as a key within a component's id breaks the new callback context's `args_grouping` function.
- [2084](https://github.com/plotly/dash/pull/2084) In dash 2.5.0, a default viewport meta tag was added as recommended for mobile-optimized sites by [mdn](https://developer.mozilla.org/en-US/docs/Web/HTML/Viewport_meta_tag)
This feature can be disabled by providing an empty viewport meta tag. e.g. `app = Dash(meta_tags=[{"name": "viewport"}])`
- [2090](https://github.com/plotly/dash/pull/2090), [#2092](https://github.com/plotly/dash/pull/2092). Fixed bug where the `path` to the `pages_folder` was incorrect on Windows.

Removed

- [2087](https://github.com/plotly/dash/pull/2087) Removed the undocumented callback context `args_grouping_values` property which was incompatible with pattern-matching callbacks.

- 3D traces are now compatible with `no-unsafe-eval` CSP rules.

Fixed

- Fix [2045](https://github.com/plotly/dash/issues/2045) import error when using pytest but `dash[testing]` is not installed.

- `legend.groupclick`
- `bbox` of hover items in event data, to support custom dash-driven hover effects
- Patch releases [2.3.1](https://github.com/plotly/plotly.js/releases/tag/v2.3.1), [2.4.1](https://github.com/plotly/plotly.js/releases/tag/v2.4.1), and [2.4.2](https://github.com/plotly/plotly.js/releases/tag/v2.4.2) containing various bug fixes.

- [1735](https://github.com/plotly/dash/pull/1735) New `dcc.Tooltip` component. This is particularly useful for rich hover information on `dcc.Graph` charts, using the `bbox` information included in the event data in plotly.js v2.4.0

Dash Table
Added

- [1729](https://github.com/plotly/dash/pull/1729) Include F#, C, and MATLAB in markdown code highlighting, for the upcoming .NET and MATLAB flavors of dash.

Dash HTML Components
Removed

- [1734](https://github.com/plotly/dash/pull/1734) Removed the following obsolete `html` elements - `<command>`, `<element>`, `<isindex>`, `<listing>`, `<multicol>`, `<nextid>`. These are obsolete and had been previously removed from the reference table.

Fixed

- [1963](https://github.com/plotly/dash/pull/1963) Fix [#1780](https://github.com/plotly/dash/issues/1780) flask shutdown deprecation warning when running dashduo threaded tests.
- [1995](https://github.com/plotly/dash/pull/1995) Fix [#1992](https://github.com/plotly/dash/issues/1992) ImportError: cannot import name 'get_current_traceback' from 'werkzeug.debug.tbtools'.

- More number formatting options due to `d3-format` upgrade.
- Many new `geo` projections.
- Improved rendering and performance of `scattergl`, `splom` and `parcoords` traces.