When I attempt to Customize my menus, there is no option for adding them, but when I close the Customization window, the min, max and close buttons flash, then disappear. If you look at the image I sent, I'm wondering if Aeropeek is the issue, but I've been using that for years and this issue in Thunderbird only appeared within the last month or so. Another thing I just noticed, in this Ask your questions page, when I upload an image, even though I see the bar below Uploaded images, so I know I did upload an image, the message next to the Browse button still says "No file selected" and it should say "X number of images uploaded do you want to upload any more" or "You have exceeded the number or size allotted for images to upload", etc.