ggvis 0.4.3 hangs Shiny app, probably invalid HTML created in ui.R

[juancentro]

Sorry that Im not able to provide specific details, as the app is very large. But when I updated to ggvis 0.4.3, the shiny app just hangs there. The problem seems to be invalid html created by ggvisOutput in ui.R, because if I remove the ggvis line, the full app works as usual. And reverting to ggvis 0.4.2 fixes the problem too.