make NSScroller not opaque
make NSScroller not opaque

guestOS/guestOS,cneira/cocotron,ruppmatt/cocotron,ruppmatt/cocotron,cyclaero/cocotron,ruppmatt/cocotron,cjwl/cocotron,gemu2015/cocotron-sierra,yuhangwang/cocotron,cyclaero/cocotron,gemu2015/cocotron-sierra,Suninus/cocotron,plasq/cocotron,cjwl/cocotron,Suninus/cocotron,cyclaero/cocotron,gemu2015/cocotron-sierra,guestOS/guestOS,Suninus/cocotron,guestOS/guestOS,cneira/cocotron,crystax/android-vendor-cocotron,Suninus/cocotron,crystax/android-vendor-cocotron,cjwl/cocotron,JackLian/cocotron,cyclaero/cocotron,ruppmatt/cocotron,crystax/android-vendor-cocotron,plasq/cocotron,cneira/cocotron,JackLian/cocotron,crystax/android-vendor-cocotron,JackLian/cocotron,guestOS/guestOS,JackLian/cocotron,gemu2015/cocotron-sierra,plasq/cocotron,cjwl/cocotron,plasq/cocotron,yuhangwang/cocotron,cneira/cocotron,yuhangwang/cocotron,yuhangwang/cocotron