click does not register after dragging the scroll handle

[xyproto]

When running the lists sample and using the Custom adapter tab, there is a tiny circular gray handle that can be used for scrolling the list of colors. When scrolling the list and quickly clicking a color, the click is not registered and the color does not change. When waiting 400ms or so, the click is registered.

Various info:

• go version go1.4.2 darwin/amd64
• OS X 10.10.4
• using the latest commit from the master branch of gxui (3777705)