I have just got the latest Mozilla/Thunderbird upgrade and it looks like that now Thunderbird on Ubuntu behaves like it were yet another stupid phone/tablet app.
Tons of clicking around to do simple operations and it is now impossible to move up and down the list of messages with the cursor and deleting them clicking on the Delete button with the mouse: either you do everything with the mouse or everything with the keyboard. Very slow and very frustrating.
Probably I am becoming more and more an old grumpy fart, but I'm getting sick and tired of new cartoonish and much less efficient GUIs.
I am afraid that this is the last straw and, unless I can configure Thunderbird to a behavior closer to the previous versions, I will drop it altogether.