I'm not sure when this started happening but lately having Firebug open prevents the JavaScript of Bootstrap 3 from functioning properly. I haven't done extensive testing but modals, scrollspy, and the navigation bar no longer work when Firebug is active. Furthermore, closing Firebug doesn't seem to resolve the issue. Only quitting Firefox fixes the problem until Firebug is activated on the webpage again. I initially thought this was a bug in my website code but I've confirmed it takes place on the
www.getbootstrap.com website as well. I haven't found any other mention of it when searching so I'm happy to do additional troubleshooting to try and narrow down the problem. Note, there are no console errors and I haven't noticed it affecting any other JavaScript functionality. Very strange.