[Backport #1791](Closed) r24205,r23960,r23892,r23871 $B$r%P%C%/%]!<%H$9$k(B

e$B%A%1%C%He(B #1791 e$B$,99?7$5$l$^$7$?!#e(B (by Yuki S.)

e$B%9%F!<%?%9e(B Opene$B$+$ie(BClosede$B$KJQ99e(B
e$BM%@hEYe(B Highe$B$+$ie(BNormale$B$KJQ99e(B

r24205, r23892e$B$r%^!<%8$7$^$7$?!#e(B

r23960e$B$K$D$$$F!“ITDjCM$N$I$l$rA*Br$9$k$+$O%1!<%9$K$h$k$H;W$o$l$k$N$G%P%0$HG’Dj$7$^$;$s!#e(BRubye$B$H$7$F$O%(%i!<$rH/@8$9$k$+e(BNaNe$B$rJV$9$Y$-$+$bCN$l$^$;$s$,!”$=$N2DG=@-$K$D$$$F$b;EMMJQ99$H$J$k$?$ae(B1.9.1e$B$G$O8=>u$r0];}$7$^$9!#e(B

r23871e$B$bL@3N$G$J$+$C$?%3!<%J!<%1!<%9$K$D$$$F$N5sF0$NJQ99$H$J$k$?$a8=>u$r0];}$7$^$9!#e(B

http://redmine.ruby-lang.org/issues/show/1791