I am converting libraries from the Arduino IDE to VS/VM, but hitting compile problems:  IntelliSense: cannot open source file "Servo.h"

I created a separate solution using only the "Sweep.ino" example from the Servo library examples and it compiled easily, so it doesn't feel like an overall problem... instead I suspect there is something in my configuration that is off.

Some critical data:
1) #include <Servo.h> resides only in the Detector.h file that depends on it.
2) Servo.h shows up in the External Dependencies folder
3) "fatal error: Servo.h: No such file or directory" occurs twice in the Error List (these are the only compile errors), and references lines  13 and 12.
4) The include statement occurs on line 12, immediately below the line "#include <Arduino.h>". 
5) Line 13 is empty. (See attached screen shots)

I have tried cleaning and rebuilding the solution without effect.

If I put the include statements into the sketch file, I get 1 error (ld returned 1 exit status collect2.exe) and 280 warnings.

Please advise...