In the newest version of Thunderbird the ability to toggle the read/unread status via the "Mark" button has gone away. The Mark button now summons a drop down menu of options. I use my mail to enter customer orders. I open a letter and copy the data to my order screen, then I mark the letter as read. I've been doing this for years. Now I hit the button and nothing happens. I know I can use the tiny green dots in the header row as a toggle but they are difficult to target because of size and when the header is highlighted they are no longer green. I know there is a keyboard shortcut but I'm a one-finger typist and that means I have to look down at my keyboard and find the "M". I really want to do this as a mouse action. Is there any way to turn a keyboard shortcut into a button? Or to modify the "Mark" button to restore the toggle function? I can't seem to stop myself from pressing the Mark button just once and then becoming distracted because the read status doesn't toggle.