I would reach out to your Account Manager as well to ensure there is a Product Commitment in place for this feature with some details that include auto window alignment, snap-to resizing, and window measurement hovers which would probably be more directly beneficial than just adding a ruler to the sides of the edit window in Edit Mode. The application I mention below does the ruler thing.
There are some general styling to keep in mind when creating a display for the web.
1) Due to the lack of "window sizing / measuring" in the IRGUI desktop interface I utilize http://www.cthing.com/Meazure.asp to measure the size of windows in terms of resolution and the screen size I am planning the screens to be leveraged on.. based on the organizations' standard display resolution. If developing on a widescreen monitor this is especially important if your end users may not have similar wide resolutions. Our minimum resolution I believe is currently 1024x768 for the WebUI before things start getting crunched but we commonly develop screens at higher resolutions.
2) The IRGUI doesn't have a good auto-align feature to ensure windows are preciously aligned and I agree I've also used the ruler, rubber band, string across the monitor to ensure alignment of the windows. On that though they I believe just need to be withing a few pixels of each other and on publishing the WebUI will auto-align within a few pixels (I don't recall what the pixel threshold is but seem to recall it is 5 or less).
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Christopher R Souser - Solution Architect – MSci. PA, CISSP, ITIL.