Seconded. decisionmodels.com has excellent stuff on the difference between F9, sh-F9 and ctrl-sh-F9, and explains when the formula graph gets rebuilt. When you'

Seconded. decisionmodels.com has excellent stuff on the difference between F9, sh-F9 and ctrl-sh-F9, and explains when the formula graph gets rebuilt. When you're building calc heavy XLL addins it's important to have a clear understanding of the behaviour of the calc engine code invoking your addin.