Task not executed if "pickString" input value is empty string

[letmaik]

• VSCode Version: 1.30.2
• OS Version: Windows 10

Steps to Reproduce:

{
    "id": "flag",
    "description": "...",
    "default": "",
    "type": "pickString",
    "options": ["", "--flag"]
}

When I use this within the args of a task like ${input:flag} and select the empty default value, then the task is not executed. The idea is to conditionally add a boolean flag to the program that is launched.

EDIT: As a work-around, it seems to work if I use a whitespace instead.