CTRL+1 is the Eclipse quick-fix key. I use it all the time but sometimes it predicts my intentions incorrectly. Take for example the following code:
I position my cursor on the field "composite_1" to rename it and press CTRL+1. What happens is the following: The tooling knows that my source contains errors and jumps to the next nearby problem to display the quick-fix options. Nice, but not what I wanted.
To get back to my original cursor position I press CTRL+1 again. The cursor jumps back and opens the quick fix dialog again but now on the correct position:
You probably knew this one but I thought I tell you anyway, just in case.
Cheers,
Wim