Anybody else having problems with the page width of OH constantly changing?

sometimes its all in screen ,sometimes its scroll to the right time & all different widths in between........shitting me.........

seems to have happened around the same time as the ads being introduced & also a firefox update.

been thru firefox,cant seem to find anything to control it,deleted cookies,everything.Havent tried IE,as something has taken over my IE & i cbf with it lately.

Only happens on OH too,am i missing something here?