📣 Dash 0.40.0 released


dash v0.40.0
dash-renderer v0.21.0
dash-core-components v0.45.0
dash-html-components v0.15.0


  • Regression fixes for Slider and RangeSlider #486, #481
  • Improved renderer performance #126
  • Updated dcc Markdown component #492
  • Support Graph restyle event #483

In Depth

setProps & callbacks
A frequent issue has been unexpected behavior when a component is not used as an input in a callback. This often caused the component not to update correctly and usually involved setting up a “hack” callback that would listen for some arbitrary value on the component in order for it to behave correctly. This should not be required anymore as described in the updated documentation:

Note: If you were using props.children.props in your components, this will no longer work. The information about the direct children can still be accessed through _dashprivate_layout like in the dcc tabs. You can also have a look at the PRs here and here for details.

  • Component type information still available but only as a type/namespace string
  • Nested children information is also still available through the nested layouts

The Markdown component update now makes it possible to use Markdown tables. It better follows the Markdown guidelines, so the resulting HTML may differ between this version and the old one.

Previous Release
Dash 0.39


Using the Tabs component in dash-bootstrap-components results in ‘Error loading page layout’ in Dash v0.40. But it works all fine with v0.39. :tired_face:

Thanks as ever!

I’m currently working on a page that has 14 callbacks that are connected to 152 props. With future plans to multiply this by 2 - 5x depending what customization we end up adding.

On Dash v0.39 it was usually taking 2.5 seconds to load but sometimes up to 6 seconds, I used the full page loading component so the user wouldn’t try to interact with the page before it was ready.

In Dash v0.40 it is usually taking less than 600ms to load, the loading component now flashes by so fast you barely notice it.

I’m not using Tabs from dash-bootstrap-components and so far all my other bootstrap-components work fine. I suggest coming up with a very simple example and reporting it here: Issues · facultyai/dash-bootstrap-components · GitHub


Thanks @Damian - i’ll do that. yes- all other dash-bootstrap-components are working fine. :slight_smile:

I was having some serious issues with this update. Really not sure what the root cause was and I should have documented/shared, but everything is back to normal after reverting to 39.0
I do know that the issues were somehow related to either the “multiple outputs” feature, or the “callback context” features released in 39.0

If you have more insight to share on the issues you’re experiencing, we’ll gladly take a look a it.