Some popup windows use a fixed size version of a browser window.
For example, the popup to edit / create a link in tinyMCE v3.
When I first opened the edit/create link window, the ID Safe drop down appears at the top, asking to log into the vault to use / store the login details.
Unfortunately, the drop down pushes the submit button out of the bottom of the window, and the X close button is missing from the ID Safe drop down.
If logged in to ID Safe, I can create / edit the link - but when I click on the options for target, the drop down appears asking if I want to fill in the form - again no X option appears, so I can't close the drop down, but it has also pushed the submit button out of the bottom of the window!