fix tube example [ssize skip]
fix tube example [ssize skip]

srinathv/vispy,michaelaye/vispy,Eric89GXL/vispy,sh4wn/vispy,RebeccaWPerry/vispy,jdreaver/vispy,bollu/vispy,drufat/vispy,inclement/vispy,Eric89GXL/vispy,jay3sh/vispy,jdreaver/vispy,kkuunnddaannkk/vispy,sh4wn/vispy,ghisvail/vispy,inclement/vispy,sbtlaarzc/vispy,inclement/vispy,srinathv/vispy,RebeccaWPerry/vispy,kkuunnddaannkk/vispy,ghisvail/vispy,jay3sh/vispy,sbtlaarzc/vispy,jdreaver/vispy,RebeccaWPerry/vispy,Eric89GXL/vispy,sbtlaarzc/vispy,michaelaye/vispy,dchilds7/Deysha-Star-Formation,QuLogic/vispy,hronoses/vispy,kkuunnddaannkk/vispy,bollu/vispy,QuLogic/vispy,srinathv/vispy,dchilds7/Deysha-Star-Formation,hronoses/vispy,hronoses/vispy,QuLogic/vispy,ghisvail/vispy,drufat/vispy,julienr/vispy,julienr/vispy,michaelaye/vispy,jay3sh/vispy,sh4wn/vispy,bollu/vispy,dchilds7/Deysha-Star-Formation,drufat/vispy,julienr/vispy