VS 201x and VS Code are not able to find real source with declarationMaps

[HolgerJeromin]

TypeScript Version: Version 3.0.0-dev and 2.9

Search Terms:
goto definition F12

Code structure
BaseControl/source.ts
BaseControl/tsconfig.json
ButtonControl/source.ts
ButtonControl/tsconfig.json with "include": [ "../BaseClass/Source.d.ts"]

When I use in ButtonControl stuff from the BaseControl the code compiles and all Intellisense works.
But using "Goto Definition" F12 shows a small popup window: "No definition found for..."
Without using declarationMap:true F12 jumps to the Source.d.ts file.

Attached is a minimal example for VS Code
ts_navigation.zip

Related Issues:
Related to #25322 but this is typescript only (no gulp-sourcemaps involved)
@weswigham

[mhegazy]

@weswigham can you take a look.