I have already replayed to your support ticket, so I am pasting my answer below for the community:
Note that we support browsers listed in Browser Support
help article only in their standards mode, which means the Compatibility View mode is not supported. That is why some issue like the mentioned one may arise in this mode.
What I can suggest you is to use the following meta tag, that disable the compatibility view:
"IE=9; IE=8; IE=7; IE=EDGE"
More information on the matter is available in this
forum thread and this
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