I've been using Muse for quite some time now and am pretty good at solving issues that have gone wrong however today I seem to have encountered an issue that has me stumped. I have 6 breakpoints on my single page website. 3 of which are fixed width for scroll features and the other three are fluid for mobile and tablet devices. The issue I'm having is when I go to my 1000px and 1200px fixed width breakpoints to make simple changes such as moving a text box or image these changes aren't applied in the preview. Even if I make changed to the scroll effects nothing happens. Often there is a change however there is no correlation between the preview and the design. I can't think what may be causing this. Could it be a widget? It's almost like the two breakpoints are synchronising. It's rather hard to explain as it doesn't actually make sense! I can upload my site to business catalyst and share the link if that helps but for now I'm completely mind boggled as to what is causing this to happen.
There are too many possibilities, why you don`t get the expected preview.
Might be good for the beginning to show us a link, even better show us a .muse.
Simply your onepage-site with just one or two elements (please delete all other elements) which you set to change between breakpoints. Share this via CC or dropbox.
It´s quite common, that you find the mistake by yourself this way .
From not seeing anything, maybe you set some pinnings? These are not necessary and mostly not helpfull.
Give it a try a watch out.