Add padding:2px;
to your #articleleftmenu
will solve your problem.
Check this JSFiddle
FYI:
There is a difference between .toggle()
and .toggle() event
See documentation:
So you use .toggle()
normally as below.
$('.sections').on('click', function() {
$( "#articleleftmenu" ).slideToggle( "left" );
});
Check this Updated JSFiddle.
Hope you understand.