Switching between Browser views in the middle of (incomplete) edit - advice?

I frequently start to edit a method, then realize I need to look at or 
change something elsewhere. The method I was editing will not Accept as-is; 
and opening a new browser interrupts my flow. What is best practice here? 
Anything equivalent to a tabbed browser, or "hold this partly-edited code, 
I'll be right back" ?

Sophie