Sets the opacity of the main mIRC window, or of desktop windows created by /window -d
setlayer <0-255> [@desktop window|@wid]
- The first parameter represents how opaque to make the window. 255 is fully opaque (or 0% transparent) and 0 is fully transparent (0% opaque)
- The second parameter can be a desktop window, or the window ID for a desktop window.