In case anyone interested my code, with hiding tweaks like Backgrounds/borders, chat tab button.
Lua Code:
--[[Show Chat/Combat Log & Undock]]--
SetChatWindowShown(2, 1)
SetChatWindowDocked(2, 0)
--[[Only Load Script When Entering World]]--
local aspect = CreateFrame("frame", nil, UIParent)
aspect:RegisterEvent("PLAYER_ENTERING_WORLD")
aspect:SetScript("OnEvent", function(self, event)
--[[Set Chat Frame Position & Size]]--
ChatFrame1:ClearAllPoints()
ChatFrame1:SetPoint('BOTTOMLEFT','UIParent','BOTTOMLEFT',5 ,5)
ChatFrame1:SetPoint("TOPRIGHT","UIParent","BOTTOMLEFT",392 ,225)
--[[Texture Tweaks]]--
ChatFrame1Background:Hide()
ChatFrame1ButtonFrame:Hide()
ChatFrame1RightTexture:Hide()
ChatFrame1LeftTexture:Hide()
ChatFrame1TopTexture:Hide()
ChatFrame1BottomTexture:Hide()
ChatFrame1Tab:Hide()
ChatFrame1TabLeft:Hide()
ChatFrame1TabMiddle:Hide()
ChatFrame1TabRight:Hide()
ChatFrame1TabText:Hide()
ChatFrame1TabHighlightLeft:Hide()
ChatFrame1TabHighlightMiddle:Hide()
ChatFrame1TabHighlightRight:Hide()
ChatFrame1TabSelectedLeft:Hide()
ChatFrame1TabSelectedMiddle:Hide()
ChatFrame1TabSelectedRight:Hide()
GeneralDockManager:Hide()
--[[Set Combat Log Position & Size]]--
ChatFrame2:ClearAllPoints()
ChatFrame2:SetPoint('BOTTOMLEFT','UIParent','BOTTOMLEFT',426 ,5)
ChatFrame2:SetPoint("TOPRIGHT","UIParent","BOTTOMLEFT",812 ,225)
--[[Texture Tweaks]]--
ChatFrame2Background:Hide()
ChatFrame2ButtonFrame:Hide()
ChatFrame2RightTexture:Hide()
ChatFrame2LeftTexture:Hide()
ChatFrame2TopTexture:Hide()
ChatFrame2BottomTexture:Hide()
ChatFrame2Tab:Hide()
ChatFrame2TabLeft:Hide()
ChatFrame2TabMiddle:Hide()
ChatFrame2TabRight:Hide()
ChatFrame2TabText:Hide()
ChatFrame2TabHighlightLeft:Hide()
ChatFrame2TabHighlightMiddle:Hide()
ChatFrame2TabHighlightRight:Hide()
ChatFrame2TabSelectedLeft:Hide()
ChatFrame2TabSelectedMiddle:Hide()
ChatFrame2TabSelectedRight:Hide()
CombatLogQuickButtonFrame_CustomTexture:Hide()
--[[Ending Script]]--
aspect:UnregisterAllEvents()
end)