Type: LanguageService

Describe the bug

• OS and Version: MacOS Mojave 10.14.4
• VS Code Version: 1.33.1
• C/C++ Extension Version: 0.23.0 (Insiders).
• Other extensions you installed (and if the issue persists after disabling them): Cortex-Debug, FreeMarker, Python. The problem persists even when I disable these.
• A clear and concise description of what the bug is.
  I use STM32CubeF4 libraries which depend on C defines to enable code sections.
  When I open one of the library files, the code is active, but after a few seconds, it becomes inactive. As you can see from screenshots, the define for I2C1 exists, but the code region is inactive. Am I doing something wrong?

To Reproduce

1. Go to ' Command Palette, and >Reload Window'
2. Click on 'any .c file' in the STMCubeF4 library and look for code regions controlled by defines.
3. I should note that the same problem is not reproduce-able in my own code. I'm not sure if the difference comes in from the larger code in the library files.
4. Also worth noticing, is that if I configure the same project in Eclipse (using SW4STM workbench), the code regions work as expected.

Screenshots