SideLock

SideLock is a small Windows system-tray utility that disables the standard Back and Forward behavior of mouse side buttons in browsers, File Explorer, and other applications.

The problem

Mouse side buttons normally send Windows Back (Mouse4) and Forward (Mouse5) commands. They are convenient Push-to-Talk buttons for Discord, but pressing them while the pointer is over a browser, File Explorer, or Discord can also cause unwanted navigation.

How it works

Mouse button	Normal Windows action	SideLock action when blocked	Discord key
Mouse4	Back	Blocks the button	F23
Mouse5	Forward	Blocks the button	F24

Each button can be blocked independently. Clearing its checkbox restores the normal Windows behavior for that button.

Usage

1. Run SideLock.exe from the publish folder.
2. Find the SideLock icon in the Windows notification area near the clock.
3. Right-click the icon.
4. Check Block Mouse4 and/or Block Mouse5.

The blocking choices are saved between launches.

Tray menu

Item	Purpose
Settings → Start with Windows	Starts SideLock when you sign in to Windows.
Block Mouse5	Blocks Mouse5 and sends F24.
Block Mouse4	Blocks Mouse4 and sends F23.
Exit	Completely exits SideLock.

Important Discord limitation

SideLock blocks standard Windows mouse messages, so browsers, File Explorer, and most applications do not receive the navigation command. Discord can also read original mouse events using Raw Input. As a result, while recording a keybind Discord may label the first side button as Mouse3; this is Discord's naming convention, not a SideLock error.

If Discord uses Raw Input in your scenario, completely hiding the physical side button from Discord requires remapping the button in the mouse manufacturer's software or using a driver-level interceptor. SideLock will still block navigation in regular applications.

Build

.NET SDK 8 or newer is required:

dotnet publish .\SideLock.csproj -c Release -r win-x64 --self-contained false -o .\publish

The built application is publish\SideLock.exe.