Inspect Incoming calls Can't calculate children Follow

Im using the Resharper Inspect function Incoming calls to see where a functions is used. But it says it "Can't caluclate children".

But when i use the references link above the function it can list the incoming calls.

I tried cleaning and restarting VS but i still doesnt work.

here the screenshot

i hope its clear what i mean

EDIT: some additional information, its a rather big project with big files, could that be problem? but i also found out that it works in some file but not in others ...