Filling out multiple snippet placeholders

We have a fairly complex snippet that includes 8 custom placeholders. Sometimes, after entering the new value for placeholders 1-4, I find I need to go to another SSMS tab and look something up in order to fill in the new value for placeholder 5. Unfortunately, when I come back to my snippet tab, I am no longer in any sort of snippet completion mode and the remaining placeholders are no longer highlighted for me enter. Is there any way to step back into the snippet completion mode and enter my other placeholders?  Or is find & replace my only viable option at that point? 

Thanks!