fix context menu in disabled state
fix context menu in disabled state

xtermjs/xterm.js,sourcelair/xterm.js,Tyriar/xterm.js,Tyriar/xterm.js,akalipetis/xterm.js,akalipetis/xterm.js,xtermjs/xterm.js,xtermjs/xterm.js,akalipetis/xterm.js,Tyriar/xterm.js,Tyriar/xterm.js,sourcelair/xterm.js,xtermjs/xterm.js,sourcelair/xterm.js,sourcelair/xterm.js,xtermjs/xterm.js,Tyriar/xterm.js,akalipetis/xterm.js