[Fizzlemizz]

I haven't used LitePanels (so backup your layout file) but a quick look at the docs and I think something like this might work, assuming you want all the panels in this layout to hide and assuming LP parents all subsequent frames to the first in a layout:

lpanels:CreateLayout("Button Bar", {
	-- Buttonbar background
	{	name = "Buttonbar",
		width = "783", height = 86, 
		y_off = 7, x_off = "552",
		bg_color = "0.1 0.1 0.1", bg_alpha = 1,
		level = 4,
                OnLoad = function(self)
                    self:RegisterEvent("PET_BATTLE_OPENING_START")
                    self:RegisterEvent("PET_BATTLE_CLOSE")
                end,
                OnEvent = function(self, event)
                    if event == "PET_BATTLE_CLOSE" then
                    	if self.PetBattleHidden then
                    		self.PetBattleHidden = nil
                    		self:Show()
                    		return
                    	end
                    end
                    if not self:IsVisible() then return; end
                    if event == "PET_BATTLE_OPENING_START" then
                    	self.PetBattleHidden = true
                        self:Hide()
                    end
                end,
	},
		-- Lines around the box
		{	name = "BB_left", parent = "Buttonbar",
			anchor_to = "LEFT",
			width = 1, height = 86, x_off = -1,
			bg_color = "0.3 0.3 0.3", bg_alpha = 1,
			level = 5,
		},
		{	name = "BB_right", parent = "Buttonbar",
			anchor_to = "RIGHT",
			width = 1, height = 86,
			bg_color = "0.3 0.3 0.3", bg_alpha = 1,
			level = 5,
		},
		{	name = "BB_top", parent = "Buttonbar",
			anchor_to = "TOP",
			width = 783, height = 1,
			bg_color = "0.3 0.3 0.3", bg_alpha = 1,
			level = 5,
		},
		{	name = "BB_bottom", parent = "Buttonbar",
			anchor_to = "BOTTOM",
			width = 783, height = 1,
			bg_color = "0.3 0.3 0.3", bg_alpha = 1,
			level = 5,
		},
})

If it doesn't work, posting in the LitePanles comments page might find someone who can massage the code correctly.