Display a popup message box
popup_messagebox(message, type, title, ...)
message to display. Required.
one of 'abortretryignore', 'ok', 'okcancel', 'retrycancel', 'yesno', 'yesnocancel'
window title
other options (experts)
See tcl/tk documentation for more information on this element https://www.tcl.tk/man/tcl8.6/TkCmd/messageBox.html
if (FALSE) {
popup_messagebox(message = 'hello')
}