sublime text terminus build cancel does nothing

Question

The title says it all, build cancel does nothing, command pallet does nothing, keybind does nothing. I have changed the keybind from prefrences with this:

{ "keys": ["ctrl+alt+c"], "command": "cancel_build" },

I have added my own Python terminus build:

{
"target": "terminus_exec",
"cancel": "terminus_cancel_build",
"focus": true,
"cmd": ["python3", "-u", "$file"],
"file_regex": "^[ ]*File \"(...*?)\", line ([0-9]*)",
"selector": "source.python",

"env": {"PYTHONIOENCODING": "utf-8"},

"windows": {
    "cmd": ["py", "-u", "$file"],
},

"variants":
[
    {
        "name": "Syntax Check",
        "cmd": ["python3", "-m", "py_compile", "$file"],

        "windows": {
            "cmd": ["py", "-m", "py_compile", "$file"],
        }
    }
]

}

(I am really new to sublime text and also to coding) Thanks in advance. Edit: I am using Windows 10, in python installer I have selected the add to PATH option and changing keybind does nothing. I use this as my test file:

while True:
   print("Stop it!")

Answer 1

There was not even a problem, the code I was running was so hard on my system that cancelling took ages. (Props to @OdatNurd for finding it)