[Fizzlemizz]

You said moving the camera so this might give you something to start/work with (as currently coded, requires mouseleft to be held down to move the camera but it's up to you):

local f = CreateFrame("Button", "SomeOnEnterFrame", WorldFrame)
f:SetSize(200, 200)
f:SetPoint("TOPLEFT")
f.t = f:CreateTexture()
f.t:SetAllPoints()
f.t:SetTexture("abc")
f:RegisterForClicks("LeftButtonDown", "LeftButtonUp")
f:SetScript("OnEnter", function(self)
    print("Entered")
    self:SetSize(400, 400)
end)
f:SetScript("OnLeave", function(self)
    print("Left")
    if self.MouseLooking or MouseIsOver(self) then
        return
    end
    self:SetSize(200, 200)
end)
f:SetScript("OnClick", function(self, button, down)
    if down then
        if not self.MouseLooking then
            self.MouseLooking = true
            MouselookStart()
        else
            self.MouseLooking = nil
            MouselookStop()
        end
    end
end)
WorldFrame:HookScript("OnMouseUp", function(self, button)
    if SomeOnEnterFrame.MouseLooking then
        SomeOnEnterFrame:Click(button, true)
    end
end)

... or not.

You can't have MouseLook "running" and interact with UI elements at the same time using the mouse.

If MouseLook gets "stuck on" while figuring out all the ins and outs you might need to address, clicking both buttons should unlock it.