Dash

- `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.

- Legend group titles
- Half-year directive (`%h`) for date formatting
- Several other bug fixes and performance improvements
- [Patch release 2.2.1](https://github.com/plotly/plotly.js/releases/tag/v2.2.1) containing a security fix.

Added
- [932](https://github.com/plotly/dash-core-components/pull/932) Adds a new copy to clipboard component.
- [948](https://github.com/plotly/dash-core-components/pull/948)] Adds `disabled_days` prop to `DatePickerRange` and `DatePickerSingle` components. With this prop you can specify days that should be made unselectable in the date picker, in addition to those that fall outside of the range specified by `min_date_allowed` and `max_date_allowed`.

Changed
- [972](https://github.com/plotly/dash-core-components/pull/972) Updated R package vignettes and `dash-info.yaml` to regenerate examples without attaching now-deprecated core component packages (`dashHtmlComponents`, `dashCoreComponents`, or `dashTable`).

Dash HTML Components
Changed
- [194](https://github.com/plotly/dash-html-components/pull/194) Updated dependencies and build process
- [190](https://github.com/plotly/dash-core-components/pull/190) Updated R package vignettes and `dash-info.yaml` to regenerate examples without attaching now-deprecated core component packages (`dashHtmlComponents`, `dashCoreComponents`, or `dashTable`).

Dash Table
Fixed
- [907](https://github.com/plotly/dash-table/pull/907)
- Fix a bug where pagination did not work or was not visible. [834](https://github.com/plotly/dash-table/issues/834)
- Fix a bug where if you are on a page that no longer exists after the data is updated, no data is displayed. [892](https://github.com/plotly/dash-table/issues/892)


Added
- [916](https://github.com/plotly/dash-table/pull/916)
- Added `html` option to `markdown_options` prop. This enables the use of html tags in markdown text.

- [545](https://github.com/plotly/dash-table/issues/545)
- Case insensitive filtering
- New props: `filter_options` - to control case of all filters, `columns.filter_options` - to control filter case for each column
- New operators: `i=`, `ieq`, `i>=`, `ige`, `i>`, `igt`, `i<=`, `ile`, `i<`, `ilt`, `i!=`, `ine`, `icontains` - for case-insensitive filtering, `s=`, `seq`, `s>=`, `sge`, `s>`, `sgt`, `s<=`, `sle`, `s<`, `slt`, `s!=`, `sne`, `scontains` - to force case-sensitive filtering on case-insensitive columns

Changed
- [918](https://github.com/plotly/dash-core-components/pull/918) Updated all dependencies. In particular the `highlight.js` upgrade changes code highlighting in markdown: we have long used their "github" style, this has been updated to more closely match current github styles.
- [901](https://github.com/plotly/dash-core-components/pull/901) Updated R package `dash-info.yaml` to regenerate example without attaching now-deprecated core component packages (`dashHtmlComponents`, `dashCoreComponents`, or `dashTable`).

- New `icicle` trace type.
- New `legendrank` trace attribute.
- Several other additions and bug fixes.

- Stop exporting d3 as `Plotly.d3`, and remove many other deep pieces of the public API. This does not affect the `dcc.Graph` component, but if you make use of `Plotly` from the global scope in some other way you may be affected.
- Drop the deprecated trace types `contourgl` and `area`, as well as legacy pre-`scatterpolar` polar attributes `bar.r`, `bar.t`, `scatter.r`, `scatter.t`, `layout.radialaxis`, `layout.angularaxis`. Use `scatterpolar`, `barpolar`, and `polar` subplots instead.
- `heatmapgl` and `pointcloud` trace types, and the `transform` attribute are deprecated, and will be removed in a future release.
- Increase CSP safety by removing function constructors. 3D plots still use function constructors, but if you place one of the non-3D bundles (including the new `strict` bundle) in your `assets` folder you will have no function constructors.
- Remove "Aa" text in legends.
- Default `hovermode` to "closest".
- Default `textposition` to "auto" in `bar` traces. If you previously used the `bar.text` attribute for hover only, you will need to explicitly set `textposition="none"`.
- Add `bar.marker.pattern`, `image.zsmooth`, and various other features and bugfixes.