Have you gotten this error? Is it sometimes accompanied by the even more rare
Failed to load view '...' because it's not a React element
If so, restart Visual Studio. These errors seem to go away when you do that. Wasn't able to find this information by Googling, so here it is for you.
Hm, that 2nd one is more intransigent than I thought. I was able to remove it by setting a breakpoint where it occurs in bundle.js, and then restarting after the breakpoint is hit. Strangely, that eliminated the error, but I'm still having issues with Visual Studio not being able to find things which are definitely there.... odd...