To the best of my knowledge, every browser does this and the functionality you're looking for cannot be done. It's ultimately a limitation of the page design itself, borders/frames/etc are drawn dynamically based on the content placed in them to facilitate the page looking correct on a wide variety of browsers/monitors/resolutions/devices/etc.
In order for the behavior you're talking about to occur, the browser would need knowledge of the dimensions of that dynamic content *before* that content exists in order to load a "placeholder" spot of the same size, which logically cannot be done, nor would you want it to be unless you like pages needing to essentially load twice. Alternatively, the page would need to be designed with static dimensions (e.g. the sidebar is *always* exactly 600px wide) to prevent that "jumping" effect. Which again, isn't done for compatibility reasons.