[Fizzlemizz]

local TabName="MyNewTab";
local TabID=CharacterFrame.numTabs+1;
local Tab=CreateFrame("Button" ,"$parentTab"..TabID, CharacterFrame, "CharacterFrameTabTemplate");
PanelTemplates_SetNumTabs(CharacterFrame,TabID);
Tab:SetPoint("LEFT","$parentTab"..(TabID-1),"RIGHT",-16,0);
Tab:SetText(TabName);
Tab:SetID(TabID)
 
local Panel=CreateFrame("Frame", "A_Test_Panel", CharacterFrame);
tinsert(CHARACTERFRAME_SUBFRAMES, "A_Test_Panel")
Panel:Hide()
Panel:SetAllPoints(CharacterFrame);
Panel.Text = Panel:CreateFontString()
Panel.Text:SetFontObject(GameFontNormal)
Panel.Text:SetText("My character panel!")
Panel.Text:SetPoint("CENTER")
 
hooksecurefunc("CharacterFrameTab_OnClick",function(self, button)
    if self:GetID() == TabID then
        ToggleCharacter("A_Test_Panel")
    end
end);