Rshiny Rstudio certain formats and widgets arent working?

Im trying to learn Rshiny code, certain aspects of it aren't working for me. For example, when I try posting the tutorial code shown here

`library(shiny)

# Define UI ----
ui <- fluidPage(
  titlePanel("Basic widgets"),
  
  fluidRow(
    
    column(3,
           h3("Buttons"),
           actionButton("action", "Action"),
           br(),
           br(), 
           submitButton("Submit")),
    
    column(3,
           h3("Single checkbox"),
           checkboxInput("checkbox", "Choice A", value = TRUE)),
    
    column(3, 
           checkboxGroupInput("checkGroup", 
                              h3("Checkbox group"), 
                              choices = list("Choice 1" = 1, 
                                             "Choice 2" = 2, 
                                             "Choice 3" = 3),
                              selected = 1)),
    
    column(3, 
           dateInput("date", 
                     h3("Date input"), 
                     value = "2014-01-01"))   
  ),
  
  fluidRow(
    
    column(3,
           dateRangeInput("dates", h3("Date range"))),
    
    column(3,
           fileInput("file", h3("File input"))),
    
    column(3, 
           h3("Help text"),
           helpText("Note: help text isn't a true widget,", 
                    "but it provides an easy way to add text to",
                    "accompany other widgets.")),
    
    column(3, 
           numericInput("num", 
                        h3("Numeric input"), 
                        value = 1))   
  ),
  
  fluidRow(
    
    column(3,
           radioButtons("radio", h3("Radio buttons"),
                        choices = list("Choice 1" = 1, "Choice 2" = 2,
                                       "Choice 3" = 3),selected = 1)),
    
    column(3,
           selectInput("select", h3("Select box"), 
                       choices = list("Choice 1" = 1, "Choice 2" = 2,
                                      "Choice 3" = 3), selected = 1)),
    
    column(3, 
           sliderInput("slider1", h3("Sliders"),
                       min = 0, max = 100, value = 50),
           sliderInput("slider2", "",
                       min = 0, max = 100, value = c(25, 75))
    ),
    
    column(3, 
           textInput("text", h3("Text input"), 
                     value = "Enter text..."))   
  )
  
)

# Define server logic ----
server <- function(input, output) {
  
}

# Run the app ----
shinyApp(ui = ui, server = server)``

the output does not format into rows like in the Rstudio tutorial page, and certain widgets such as the selectInput widgets do not work

I dont really understand how this is possible because I copy and pasted the code directly from the Rtutorial, and it has held true when I copy and pasted example code from other websites as well! Certain widgets do not work and the formatting doesn't work at all, is there an issue with my Rstudio?

I can only input one image since I am a new user, but the Rstudio code is available here

is there something wrong with my Rstudio? I dont know how it could be the code since its directly frlm the tutorial, and the same issues persist with code that was working earlier for me but is not working right now.

Not sure what could be the reason. however when i copy the code and run it works. May be you need to check the console for any warnings that might help us to know about the issue

There weren't any warnings on the console which was odd, But I think something was wrong with my Rstudio, since I couldnt even delete and reinstall the packages

I deleted R and RStudio and Redownloaded them both and that seemed to solve the problem, it was a bit odd though