Windows user. I changed my bat file to use "start calibre" and it worked
Code:
@ECHO OFF
:: set envs
set CALIBRE_CONFIG_DIRECTORY=D:\AppData\Calibre
set CALIBRE_CACHE_DIRECTORY=D:\Temporary\Calibre\cache
set CALIBRE_TEMP_DIR=D:\Temporary\Calibre\temp
set CALIBRE_DEVELOP_FROM=D:\Documents\git\calibre\src
:: run calibre from source
start calibre
:: "c:\Program Files\calibre2\calibre.exe"
:: "c:\Program Files\calibre2\calibre-debug.exe" -g