Trying Visual Micro for the first time, so the following issue is likely my own lack of understanding.

Trying to fix Intellisense issues on the BlinkWithoutDelay example (pinMode, digitalWrite, LED_BUILTIN are highlighted etc.). Code copy/paste from Arduino IDE into a new project, or opening the existing example project from VS makes no difference.

After reading many similar topics on the forum I've updated to 1902.8 but the issue remains. 

My config:
- IDE Locations is setup for Arduino 1.6/1.8, and custom board https://dl.espressif.com/dl/package_esp32_index.json
- Selected board is SparkFun ESP32 Thing
- Board Platform Installer is esp32 v1.0.1
- adding any #includes gives the error "cannot open source file" (but project still builds)

A path issue to esp32 libraries? Any help would be appreciated.

Yes that basic project does build OK.

However I've just noticed projects that use servo.h do not. It attempts to build with the AVR servo library. I've copied "ESP32_Arduino_Servo_Library" (downloaded from https://github.com/RoboticsBrno/ESP32-Arduino-Servo-Library) to both:
- C:\Program Files (x86)\Arduino\libraries
- USER\Documents\Arduino\libraries
and double clicked "ServoESP32" in Micro Explorer, (which references the first path above)

Thanks for your help