How to disable Tab key in Gmail (Chrome or Safari) My grandpa has suffered from a very annoying "problem" in Gmail (on Mac OS under Chrome) for a long time and unfortunately I haven't found a solution for him yet: 

When composing in Gmail, each time he types a, he often accidentally presses Tab at the same time (a and Tab are next to each other), which points the focus to the Send button and when he presses Enter (for a new line); the email is unintentionally sent. 

This happens to him very often (please don't blame my old grandpa, this problem also happened to a lot of people: https://productforums.google.com/forum/#!msg/gmail/Y9DjPEA_6sk/V7IzWt02iugJ).

I hope that somebody here can help me to find a solution. I would appreciate it a lot! Thank you very much in advance!
My solution would be to use ControllerMate to intercept the Tab and do nothing with it.

ControllerMate has the ability to have workflows specific to different applications but triggered by the same key presses. (see Application Specific Programming)



While most of the examples on the site show how you can do something with a key press, you can also choose to turn off the key (disable) or reprogram it to insert 4 spaces (make it a functional tab).

ControllerMate is free for up to 10 "building blocks" so if you are trying to reprogram just your Tab, it should be completely free for this solution.