Not showing on web page

I have a problem as I have put 2 of your page viewers on the same page as part of a test for a future project, so there should be 2 showing on the page above IDIBC Fixture 11 and IDIBC Fixtures 12. However if you move to another page on the site and come back to above page sometimes only 1 shows up or on one occasion neither showed up most strange. This is only on a test theme so please ignore the actual website I was just testing your pdf viewer on this development domain which I use before constructing the main website a friend wishes me to make for him. I have tested it on IE, Chrome and Netscape all with same results. Hopefully you may be able to fix this bug in what I think is a very useful plugin. Thx Peter

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