r - RStudio snippet not working -

i'm utilizing macbook pro running "el capitan" , rstudio version 0.99.902. i'm writing rmd document. want utilize snippets rstudio has built in , create own also. clicking preference => code; can see "enable code snippets" checked. however, while trying utilize snippet completion not performed. if typed r should block of code, nothing hapen

snippet r     ```{r ${1:label}, ${2:options}}     ${0}     ``` 

i create simple snippet:

snippet dthen     %>% 

none of markdown snippet seems work. i'm doing wrong or setting has done?

you can invoke code snippets in markdown in rstudio using shift+tab after typing snippet, not prompt expand snippet, either tab or waiting. thought bug, discussion in github issue says it's intended, still-to-be-documented.