I also noticed several projects and targets are not exportable to vscode_gcc_arm (but can export to others like vscode_armc5).
For example, if I target bbc micro:bit (nrf51 based), and export to vscode_gcc_arm, I get an unhelpful error "An error occurred during export. Please contact support." I suspect that because for whatever reason, micro:bit support is not yet available for mbedos5.x, that this wont work, but it would be better for the UI to tell us why we can't export to a particular project type.
Then on others, like Nordic nRF51-DK, which is supported w/ mbedos5.x, I can export a project and load it in vscode, however, there seem to be many broken things about it - it doesnt "just work" (even after setting up debug env as documented in the mbed wikis).
E.g. launch.json, settings.json, and tasks.json are all exported in the root of the project, but seems like vscode wants them to be located in .vscode - things don't work until I move them to .vscode dir.
There were some other things, but seems like this is related to the target/platform (nrf51, e.g. way it uses soft devices, and requires some special options on pyocd-gdb, e.g. halt after reset, use hw breakpoints, etc)
I would really love to use vscode, but seems very "alpha" at the moment.
I wonder where the right forum or place to discuss this is?
Exporting a Visual Studio Code do not work, not from online compiler, not from personal repository. For examples this public project https://os.mbed.com/users/testato/code/Testato-mbed-dev-Bluepill/