While Beta 2 saw the bulk of our breaking changes during the beta phase, but we still have a few that needed to be addressed in the Beta 3 release. These changes apply if you're updating to Beta 3 from Beta 2 or any older version of Bootstrap.
### Miscellaneous
- Removed the unused `$thumbnail-transition` variable. We weren't transitioning anything, so it was just extra code.
- Changed the CSS for managing multiple `background-image`s on custom form checkboxes and radios. Previously, the `.custom-control-indicator` element had the background color, gradient, and SVG icon. Customizing the background gradient meant replacing all of those every time you needed to change just one. Now, we have `.custom-control-indicator` for the fill and gradient and `.custom-control-indicator::before` handles the icon.
- The npm package no longer includes any files other than our source and dist files; if you relied on them and were running our scripts via the `node_modules` folder, you should adapt your workflow.
### Forms
- Rewrote both custom and default checkboxes and radios. Now, both have matching HTML structure (outer `<div>` with sibling `<input>` and `<label>`) and the same layout styles (stacked default, inline with modifier class). This allows us to style the label based on the input's state, simplifying support for the `disabled` attribute (previously requiring a parent class) and better supporting our form validation.
As part of this, we've changed the CSS for managing multiple `background-image`s on custom form checkboxes and radios. Previously, the now removed `.custom-control-indicator` element had the background color, gradient, and SVG icon. Customizing the background gradient meant replacing all of those every time you needed to change just one. Now, we have `.custom-control-label::before` for the fill and gradient and `.custom-control-label::after` handles the icon.
To make a custom check inline, add `.custom-control-inline`.
- Updated selector for input-based button groups. Instead of `[data-toggle="buttons"] { }` for style and behavior, we use the `data` attribute just for JS behaviors and rely on a new `.btn-group-toggle` class for styling.
- Removed `.col-form-legend` in favor of a slightly improved `.col-form-label`. This way `.col-form-label-sm` and `.col-form-label-lg` can be used on `<legend>` elements with ease.
