selectInput: use BS 3 styling when multiple && !selectize. Closes rstudio#724

Author: wch

R/bootstrap.R

@@ -793,7 +793,11 @@ selectInput <- function(inputId, label, choices, selected = NULL,
   } else selected <- validateSelected(selected, choices, inputId)
 
   # create select tag and add options
-  selectTag <- tags$select(id = inputId, selectOptions(choices, selected))
+  selectTag <- tags$select(
+    id = inputId,
+    class = if (multiple && !selectize) "form-control",
+    selectOptions(choices, selected)
+  )
   if (multiple)
     selectTag$attribs$multiple <- "multiple"