Symbol appeared and icons grayed out. How to fix?

[BobbyJazz]

A "T" appeared over the W-write icon on all of my tracks. What does it mean, how did it get there, and how do I get rid of it? Also on a blank midi track, that has a soft synth inserted, the mute, solo and record buttons are grayed out on this track only. Why, and how do I fix it? 

[scook]

Automation Write Modes