In master builds, Web pages loaded in the browser app currently display <input type=range> with the border and background styling that buttons should have. The issue is that B2G master (currently m-c is at v23) checks out a gaia that still pulls in the v18 xulrunner sdk, and uses the forms.css file from that sdk rather than using the forms.css file in the master tree's 'gecko' directory. This old v18 forms.css obviously doesn't have the style rules that were added in the v22/23 version of the file for <input type=range>, so the wrong 'input' element styling gets applied to <input type=range>. I'm filing this purely so that this is on file in the hope of avoiding having anyone spend time debugging this. There's no action needed, I'd assume, since the correct action is "have the versions of b2g, gaia, gecko and the xulrunner sdk all match", and I would sure hope we'll make sure that's the case for actual releases.

Firefox OS is not being worked on