rstudio/ggvis — pull request #231 by robertzk (2014-08-01 04:11:06+00:00)
Title: Force as.character(html) in show_tooltip

.... to ensure `shiny.tag` objects get displayed properly.

In particular, [read about the problem more in detail at StackOverflow](http://stackoverflow.com/questions/25070302/shiny-ggvis-and-add-tooltip-with-html).