I created an HTML block and added the following <object> tag via the HTML editor.
<object id="embeddedhtml" width="190" height="150" type="text/html" data="http://www.musapp.com/timer.php"></object>
I selected "Display throughout the entire site" and saved the new block.
This HTML block is displayed on every page and the <object> tag works except in the Lesson Activity.
The HTML block is displayed but it does not load the page in the <object> tag. If I open the HTML block that is displayed on the Lesson Page, it still has the <object> tag.
This problem might be related to a bug I posted at http://tracker.moodle.org/browse/MDL-23314.
For some reason I can't upload the screen shots but you can see the HTML block (called "Session Timer") at:
http://www.musapp.com/Cm2Pm/course/view.php?id=23 (working in top right block)
http://www.musapp.com/Cm2Pm/mod/lesson/view.php?id=1532 (NOT working in top right block)