Why can't I paste a password into a password form on a webpage?

On my Snow Leopard Mac, I can't seem to paste into a password field on login pages to Apple sites, (developer.apple.com for example). I thought is was a browser issue but it's happening with Safari, Chrome and Firefox so it must be the System. I assume this is somebody's idea of a security feature, though I fail to see the logic and it's very annoying.

Any ideas on how to fix, turn off or work-around this?

Solution 1:

Right-click on the password field and under the menu that appears, select "paste" (it happens to me in Firefox and that is my fix).

Solution 2:

Use the Web Inspector in WebKit based browsers and remove the onpaste="return false;" attribute and you'll be able to paste your password.