shiny-reactivity

Note: After coming up with the answer I reworded the question to make if clearer. Sometimes in a shiny app. I want to make use of a value selected by the user for a widget, as well as the previous value selected for that same widget. This could apply to reactive values derived from user input, where I want the old and the new value. The problem is that if I try to save the value of a widget, then the variable containing that value has to be reactive or it will not update every time the widget changes. But, if I save the the value in a reactive context it will always give me the current value,

I want two different events to trigger an observer. It was suggested here that this should work. But it seems that it depends only on the second event. observeEvent({ input$spec_button mainplot.click$click }, { ... } ) Have a look at the example. ui <- shinyUI(bootstrapPage( actionButton("test1", "test1"), actionButton("test2", "test2")) ) server <- shinyServer(function(input, output) { observeEvent({ input$test1 input$test2 }, { print('Hello World') }) }) shinyApp(ui, server) Once you click button test1 nothing happens. If you click button test2 it prints to your console. Once test2 button

I am trying to have a DT that is editable by the user but I only want certain columns to be editable. Since this isn't a feature yet in DT , I am trying to hack it together by having the table refresh back to the original value when edited a column that I want "locked". Below is my code: library (shiny) library (shinydashboard) library (DT) library (dplyr) library (data.table) rm(list=ls()) ###########################/ui.R/################################## #Header---- header <- dashboardHeaderPlus() #Left Sidebar---- sidebar <- dashboardSidebar() #Body---- body <- dashboardBody( useShinyjs(),