Workaround for the RocketChat/Rocket.Chat.Electron #380 Issue. Place these two files in some directory. Create a shortcut to the .bat script and run it whenever your Rocket Chat Client is hidden on the disconnected second Screen. It stops RocketChat, fixes a config and restarts it afterwards.

Rocket_Chat_Fix_Window_Position.ps1

<#
    .SYNOPSIS
    
    Workaround for the Multi-Monitor Issue: RocketChat/Rocket.Chat.Electron #380

    .DESCRIPTION
    
    This script assumes that Rocket Chat is running. It extracts the path to the Rocket
    Chat executable and stops the Rocket Chat Client afterwards. Then the json file that
    containts the clients window state gets updated and Rocket Chat will be restarted.

    (Just a quick and dirty workaround, no warranties of any kind...)
    
    .NOTES
    Author: Maurice B.
    Github: https://github.com/MauriceBrg
#>

# Stop on error
$ErrorActionPreference = "stop"

# Change this to "Continue" if you want to see the output
$DebugPreference = "SilentlyContinue"

# Path to the file where the Window State is stored
$WindowStateFilePath = ("{0}\Rocket.Chat+\window-state-main.json" -f $env:APPDATA)

# Fetch the path where RocketChat is installed fromt the currently running instance
$RocketChatPath = (Get-Process -Name Rocket.Chat+ | Select-Object Path)[0].Path

Write-Debug ("Path to RocketChat executable: {0}" -f $RocketChatPath )

Write-Debug "Stopping running Rocket Chat instances"
$StopResult = Get-Process -Name Rocket.Chat+ | Stop-Process -Force

Write-Debug "Fixing the Window Position Config"


# Read the file, parse it's content, update the x-value and save it again.
$WindowState = Get-Content -Path $WindowStateFilePath | ConvertFrom-Json
$WindowState.x = 0
$WindowState | ConvertTo-Json | Out-File $WindowStateFilePath -Force

Write-Debug "Updated the Window Position Config"

Write-Debug ("Restarting RocketChat from {0}" -f $RocketChatPath)
Start-Process -FilePath $RocketChatPath

RocketChatWindowFix.bat

REM Run the Powershell Script to fix the Rocket Chat bug that lies relative to the script location
SET ScriptLocation=%~dp0
powershell -ExecutionPolicy Bypass -WindowStyle Hidden %ScriptLocation%Rocket_Chat_Fix_Window_Position.ps1

Workaround for RocketChat/Rocket.Chat.Electron#380 on Windows.