An example illustrating a possible bug in the Leaflet package

leafletBug.R

library(shiny)
library(shinydashboard)
library(leaflet)

header <- dashboardHeader(
    title = "Example",
    titleWidth = "600px"
)

sidebar <- dashboardSidebar(width = "600px")


body <- dashboardBody(
    bootstrapPage(
        
        tags$script(
            '$(".sidebar-toggle").on("click", function() { $(this).trigger("shown"); });'
        ),
        tags$head(tags$style(
            HTML('
            section.content{
                padding:0px;
            }
            .outer {
                 height: calc(100vh - 50px);
                 padding: 0px;
                 margin: 0;
                 }
                 '))),
        tags$div(class = 'outer', leafletOutput("map",height = "100%", width = '100%'))
    )
)

ui <- dashboardPage(header, sidebar, body)        

server <- function(input, output) {
    
    
    output$map <- renderLeaflet({
        
        pal <- colorNumeric("Set2", quakes$mag)
        
        leaflet(quakes) %>% 
            addTiles() %>%
            fitBounds(~min(long), ~min(lat), ~max(long), ~max(lat)) %>% 
            addCircles(radius = ~10^mag/10, weight = 1, color = "#777777",
                       fillColor = ~pal(mag), fillOpacity = 0.7, popup = ~paste(mag)
            )
    })
    
}

shinyApp(ui,server)