I am trying to use some Build Properties to upload two 'versions' of the same code to two ESP32 modules, depending on the COM port I have selected within vMicro. 

The code compiles and runs correctly if I manually #define a parameter at the start, but that requires me to add/remove it for every upload. Utilising the build properties should remove this step, so I select the correct board and the code automagically reconfigures.

The problem is that I get the following error from intellisense. The code still compiles correctly, but intellisense is essentially disabled when writing code.

E0992	command-line error: invalid macro definition: COMPORT {serial.port.num}	<PROJECTNAME> <FILENAME> line #1  

All files within the project have the dreaded red squiggle under the first character, and the error above updates <FILENAME> according to whichever .cpp file is active.

I have tried adding the macro definition to both "Current Configuration" and "Project Global" sections of the Project Properties and the intellisense error remains. The same goes for Debug/Release configs.

Thank you for explaining the reason intellisense can't handle it. It's frustrating, but I understand the limitation.

There are no further definitions that are specific to either of the target devices, it's just some print functions that change. Thus I have no need to create individual configurations as one simple #define at the top switches the whole code from device A to device B.

Following on from your comment about future releases, it would be great if one could force some of the selectable options such as COM port, Board Type, etc., to be determined by the configuration.