In the M3 beta theme, FlowPanels end up with an anvil-flow-panel-gutter class instead of a flow-panel-gutter class.
It wasn’t a big deal, it just took a few minutes to work out why my usual FlowPanel roles didn’t work.
Is there a list of changed classes anywhere?
This only happens when creating a new M3 app
In new M3 apps all anvil classes on anvil components are now prefixed with anvil-
This is to avoid conflicts with other themes.
Note - If you add M3 as a dependency to an existing app this will not happen.
The setting can be found - in any app that is using Layouts:
Settings → Python Versions → Advanced Features → Legacy Features.