RegEx Pipe sympol

I have stumbled upon a regex trap that is most likely quite common in AutoHotkey.

Use Case

Check if WinTitle ends with | ApplicationName. It is quite common to have appended after a pipe in Windows the application name - especially for browser windows.

In my case it was for Microsoft Teams opened in the browser, see Teams Shortcuts support for browser/ app.

Trap

In RegEx the pipe symbol has an OR effect.

So this function

SetTitleMatchMode, RegEx

If WinActive("| Microsoft Teams$")

    return True

return False

will always return true.

Fix

You need to escape the pipe symbol with a \ backslash

This is the new Teams_IsWinActive function:

Teams_IsWinActive(){

; Check if Active window is Teams client or a Browser/App window with a Teams url opened

If WinActive("ahk_exe Teams.exe")

    return True

SetTitleMatchMode, RegEx

If WinActive("\| Microsoft Teams$")

    return True

return False

}

See also

Teams Shortcuts support for browser/ app | Thierry Dalon's Blog