actions do nothing on Windows — what is correct syntax to open a file?

[dominatos]

Problem
On Windows, clicking menu items that use shell= does nothing. The menu renders correctly but no action is triggered.

Environment
OS: Windows11
Platform string returned by crossbar.platform(): windows

Test plugin
I wrote a debug plugin trying every possible syntax I could think of:

lua-- test-open.1m.lua
local raw_platform = crossbar.platform()
local platform = string.lower(raw_platform or "")
local TEST_FILE = 'C:\\Users\\user\\folder1\\folder2\\file.md'

print('🧪 Test open')
print('---')
print('Default (cmd start) | shell=cmd.exe param1=/c param2=start param3="" param4="' .. TEST_FILE .. '" terminal=false')
print('---')
print('explorer.exe | shell=explorer.exe param1="' .. TEST_FILE .. '" terminal=false')
print('---')
print('cmd start no-title | shell=cmd.exe param1=/c param2=start param3="' .. TEST_FILE .. '" terminal=false')
print('---')
print('powershell Start-Process | shell=powershell.exe param1=-NoProfile param2=-Command param3="Start-Process -FilePath \\"' .. TEST_FILE .. '\\"" terminal=false')
print('---')
print('powershell Invoke-Item | shell=powershell.exe param1=-NoProfile param2=-Command param3="Invoke-Item \\"' .. TEST_FILE .. '\\"" terminal=false')
print('---')
print('rundll32 | shell=rundll32.exe param1=url.dll,FileProtocolHandler param2="' .. TEST_FILE .. '" terminal=false')
print('---')
print('simple start | shell=cmd.exe param1=/c param2=start param3=' .. TEST_FILE .. ' terminal=false')
print('---')
print('Open file terminal=true | shell=cmd.exe param1=/c param2=start param3="" param4="' .. TEST_FILE .. '" terminal=true')
print('---')
print('Open via bat | shell=C:/Users/fedorenko/crossbar_open.bat param1="' .. TEST_FILE .. '" terminal=false')
print('---')
print('platform: [' .. tostring(raw_platform) .. '] | color=gray')
print('---')
print('Path: ' .. TEST_FILE .. ' | color=gray')

Result
All items render in the menu but none of them open the file when clicked. No error, no action, nothing happens.

Question
What is the correct syntax to open a file with its default application on Windows from a Lua plugin? Is there a working example?

[dominatos]

Hello @insign . I'd appreciate if you could take a look at this.