Disabling skins is under the graphic detail section of the clipboard.
To get to the settings for graphic detail, from the clipboard menu click Options->Graphic Detail.
Disable other plane skins is used to disable seeing other plane skins. Use this if you are constrained on memory in your computer (i.e. less than 512MB of RAM, for example).
Put a check in the disable other plane skins and your good to go.
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