Same file opened twice with different filename casing

[markusjohnsson]

• VSCode Version: 1.9.0
• OS Version: OS X 10.11.6

Steps to Reproduce:

1. create file a.ts (note lower case)

import B from "B";

2. create file b.ts (note lower case)

export default class B {}

3. create file tsconfig.json

{
    "compilerOptions": {
        "module": "system"
    }
}

4. save all files
5. close all editors (cmd+w multiple times)
6. open a.ts
7. place cursor att the first B
8. hit F12
9. click on b.ts in explorer

Now b.ts is opened twice. Once as b.ts, once as B.ts and the two editors are independant with regards to save state.

[pitAlex]

I'm experiencing a slightly different behavior related to files opening twice. I don't have an exact way on how to replicate it but with same system as mentioned above I often get the file I'm working on opened again in a new tab like in the following screenshot. It mostly happens when I press cmd+s.

[bpasero]

#12448