Button "show/hide elevation chart" only visible after a route is drawn

[mendberg]

When BRouter-web is opened without a route, the "show / hide elevation" button is not visible while the (empty) elevation chart sometimes is.

Steps to reproduce:

0. clear browser cache
1. open BRouter-web, draw a route, display elevation chart
2. open 2nd Browser tab with BRouter-web (without! a route)

BRouter shows a text indicating the user to start drawing a route ("Route zeichnen, um Statistiken zu sehen.") and also an empty elevation chart (see screenshot attached: window on top). The button to hide (/show) the elevation chart is not visible, while in my opinion it should be; maybe it also makes sense to not display the elevation chart without a route drawn.

Tested with up-to-date chromium browser on Manjaro linux.