Can I use the bookmarklet toolbar on pages that contain IFrames?

Yes - the toolbar will work for all the content on the main page, however content inside the IFrames cannot be annotated due to browser security restrictions. 

The toolbar will display a message if it detects a large amount of content on the page is contained within IFrames. You'll notice that your cursor won't reflect the currently selected tool when you mouse over the content in an IFrame. 

If the content you wish to annotate is in an IFrame, you have a few options. Some sites use IFrames to put their header bar on top of content from another site. In this case, sometimes you can go directly to the IFramed site. If that isn't available, sometimes you can force the content to open as its own webpage where the toolbar will work.

• For Firefox, right-click on the frame of interest, and in the pop-up menu click "This Frame"->"Show Only This Frame" and then load the bookmarklet as usual.
• For Safari, right-click on the frame of interest, and in the pop-up menu click "Open Frame in New Tab" and then load the bookmarklet as usual.
• Internet Explorer and Google Chrome do not offer options to easily open an IFrame in a page by itself.