permanent vertical scrollbar
When a design uses a content area which is centred within the browser window you may frequently notice a ‘jolt’ as you click from a page where the content fits in the window to one where the browser has inserted scrollbars on the browser window.
This is caused by a slight reduction in the body width (and consequently the center line) from one page to another.
You can get round this problem by adding a 'overflow-y:scroll;' parameter to the body.
Unfortunately it doesn’t validate although it is supported by both gecko and I.E. and is simply ignored by other browsers.
August 30th, 2007 at 8:35 pm
http://www.communitymx.com/content/article.cfm?cid=528A0 gives a solution for a permanent vertical scrollbar that validates. You can force a vertical scrollbar by adding the following to your css:
html { min-height: 100%; margin-bottom: 1px; }
This code increases the page height by 1px more than the maximum, forcing a vertical scrollbar. Downside is that some people get annoyed by having this scrollbar there.