Example of selectize drag-and-drop in Shiny 0.12.2.9000 or higher

server.R

library(shiny)
library(DT)

dat <- mtcars

shinyServer(function(input, output, session) {
	output$ui_view_vars <- renderUI({
	  vars <- colnames(dat)

	  ## using selectizeInput with drag_drop and DT
	  selectizeInput("view_vars", "Select variables to show:", choices  = vars,
	   selected = vars, multiple = TRUE,
	   options = list(plugins = list('remove_button', 'drag_drop')))
	})

	output$dataviewer <- DT::renderDataTable({
	  if (is.null(input$view_vars)) return()
	  DT::datatable(dat[,input$view_vars])
	})
})

ui.R

shinyUI(fluidPage(
  sidebarLayout(
    sidebarPanel(
      uiOutput("ui_view_vars")
    ),
    mainPanel(
      tabPanel("View", DT::dataTableOutput("dataviewer"))
    )
  )
))