Issue with the width of the sidebar:
When using a Fluid width the side bar is set as a % and there does not appear to be an override so that it can be a fixed width in PX.
Have a random width sidebar makes it difficult to layout modules as not all modules support resizing like this. Please allow the option to set % or PX regardless of the page being responsive or fixed.
As the Fluid/Responsive layout has so many issues with the header, logo, Title text and slogan being positioned incorrectly while resizing, Fluid is difficult enough to make useable without adding this issue.