"MainPanelSeparatorMargin" doesn't work anymore or am I doing something wrong?
Those elements seems broken too (or aren't supported anymore):
<element id="MainPanelMargin.Top">2</element>
<element id="MainPanelMargin.Bottom">2</element>
<element id="MainPanelMargin.Left">2</element>
<element id="MainPanelMargin.Right">2</element>
Whatever the value, there is no margin. If I remove them from the skin file, the margin appear.