I am using the Chromium web browser, and standard gnome (i.e. not unity). Chromium (like lots of things) has many tabs, and allows you to middle click on a tab to close the tab. But if I middle click on the blue part outside the tab, then it lowers the window underneath all the other windows. However I often find myself attempting to middle click on a tab to close it, and accidentally middle clicking outside the tab (which is the title bar in chromium), and hence accidentally lowering the window.
How do I disable this "middle click to lower window" behaviour?