I used to deal with this with a lot of customers. I would recommend looking at the help file and do a search of "IE" and look at all the system requirements. It could be your IE version. Mitel only recently started to work with IE 10 and there are a ton of compatibility requirements. I find if you follow the requirements to a T, you shouldn't have an issue. Every time I've encountered someone having issues with basic browser functions, display issues, copy paste, it's always been a compatibility or IE setting.
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