What is the shortcut key to back to the previous tab?

Question

For example, after clicking open declaration, is there a shortkey which let me back to the previous tab?

Answer 1

If you are talking about switching between open files, you can do this using Ctrl+PgUp and Ctrl+PgDn

If it is about navigating back & forth to the last modification, use Alt+⇨ (right arrow) and Alt+⇦(left arrow)