VisNetwork and dashboardSidebar create footer when defining height - r

Question

I am developping a Shiny app relying on VisNetwork to plot dynamic overviews of our company's network.
Since the network is rather large, I'd like that it can extends vertically so as to make it more readable. Currently it works but then the network overlaps with the dashboardSidebar, at the bottom:
See this screenshot.
Why does the dashboardSidebar extends horizontally at the bottom, isn't only supposed to be left-sided ?
Is it possible to remove this footer?
Here is a simple reproducible example (I believe the issue arises when setting up the Height argument of the VisOptions function):
library(shiny)
library(visNetwork)
library(shinydashboard)
# User interface
ui <- dashboardPage(
dashboardHeader(title = "Network", titleWidth = 220),
## Sidebar content
dashboardSidebar(width = 220,
sidebarUserPanel(name = "CTU",image = "unibe_logo_mh.png"),
sidebarMenu(id = "tab",
menuItem('CTU Division',
menuSubItem("Data Management", tabName = "datamanagement", icon = icon("database")),
menuSubItem("Statistics", tabName = "statistics", icon = icon("chart-area")),
menuSubItem("Clinical Study Management", tabName = "studymanagement", icon = icon("laptop-medical")),
menuSubItem("Monitoring", tabName = "monitoring", icon = icon("check")), # Would like to use the "magnifying-glass"
menuItem("Quality Management", tabName = "qualitymanagement", icon = icon("broom"))),
radioButtons("projectlab", label = "Project labels", choices = c("IDs", "Names"), inline=T),
selectInput("servicetype", label = "Service", choices = c("\a", "Basic", "Full", "Light")),
checkboxGroupInput('projecttype', "Project types", c("External", "Consulting","Internal","FTE"), selected = "External"),
selectInput("dlfsupport", label = "DLF support", choices = c("\a", "Yes", "No")),
selectInput("cdms", label = "CDMS", choices = c("\a","REDCap", "secuTrial", "Webspirit")),
checkboxGroupInput('tables', "Export tables", c("Time Bookings","Workers","Projects"), selected = c("Time Bookings","Workers","Projects")),
downloadButton("DownloadReport", "Download Report", style = "margin: 5px 5px 35px 35px; "))),
## Body content
dashboardBody(tags$head(tags$style(HTML(".main-sidebar { font-size: 15px; }"))), # Changing sidebar font sizes
# Boxes need to be put in a row (or column)
fluidRow(
visNetworkOutput("network") # Unique name for an output
))
)
server <- function(input, output, session) {
getDiagramPlot <- function(nodes, edges){
v <- visNetwork(
nodes,
edges
) %>%
visPhysics(stabilization = TRUE, enabled = F) %>%
visOptions(height = "1800", highlightNearest = T, nodesIdSelection = T, selectedBy= list(variable="group",multiple=T)) %>%
visEdges(color = list(highlight = "red")) %>% # The colour of the edge linking nodes
visLayout(improvedLayout = TRUE) %>%
visEdges(arrows = edges$arrows) %>%
visInteraction(multiselect = F) %>%
visEvents(doubleClick = "function(nodes) {
Shiny.onInputChange('current_node_id', nodes.nodes);
;}")
return(v)
}
testFunction <- function(node_id){
print(paste("The selected node ID is:", node_id))
}
nodes <- data.frame(id = 1:3, label = 1:3, group = c("group1","group1","group2"), value = c(10,10,11), color=c("#E41A1C","#48A462","#4A72A6"))
edges <- data.frame(from = c(1,2), to = c(1,3), width = c(0.4,0.8))
output$network <- renderVisNetwork(
getDiagramPlot(nodes, edges)
)
observeEvent(input$current_node_id,{
testFunction(input$current_node_id)
})
}
shinyApp(ui, server)
Best,
C.