It seems that with 8.0 the scale of the MultiBar (actionbars at the right edge) is adjusted depending on how much vertical real estate there is below the minimap.
My minimap is in the bottom right corner, which apparently would result in a (weakly) negative scale, because i get the following error
18x MultiBarRight:SetScale(): Scale must be > 0
[C]: in function `SetScale'
FrameXML\MultiActionBars.lua:85: in function `MultiActionBar_Update'
FrameXML\InterfaceOptionsPanels.lua:1184: in function `InterfaceOptions_UpdateMultiActionBars'
[string "*:OnLoad"]:4: in function `setFunc'
FrameXML\InterfaceOptionsPanels.lua:1154: in function <FrameXML\InterfaceOptionsPanels.lua:1147>
Any ideas how to stop them from trying to set a negative scale?