fix margin for no open editor panes
fix margin for no open editor panes

Gaurav0/ember-twiddle,ember-cli/ember-twiddle,knownasilya/ember-twiddle,knownasilya/ember-twiddle,ember-cli/ember-twiddle,knownasilya/ember-twiddle,Gaurav0/ember-twiddle,ember-cli/ember-twiddle,Gaurav0/ember-twiddle