When I open a page in the latest RSD I get a message that some breakpoints are hidden behind the control panel on the right. True. The suggested fix, however, is another story. On a monitor with a native resolution of 1680x1050 the slider disappears at 1331 pixels. Sliding the app left as suggested makes the right side accessible but it cannot be dragged farther to the right. I can gain some additional width by changing the monitor resolution to 1920x1080 but I still can't see or design for desktop systems using the 1680 pixel width. Since the Coffee Cup site shows full width on my 1680x1050 setting you guys must have a solution, but it puzzles me.

If I am understanding your question, what you really want to do is have a page be viewable in the browser at full-width. If that is the case, design without a breakpoint to begin with. Set the max-width to none for the rows that should stretch the full width. Recognize that what you design will stretch full-screen even if the viewable area in RSD is smaller than your full screen.

Once you have your initial full screen design done, preview it in your browser and make sure it appears as you want it to appear.

After the full screen version appears like you want it, move the slider to the left until something doesn't appear correctly. Set a breakpoint and adjust the settings to make it appear correctly.

Repeat the process of moving the slider, setting breakpoints and changing settings until you get down to about 350 pixels.