When exiting a story, the maps for that story kept loaded

[ctwhome]

Describe the bug A clear and concise description of what the bug is.

To Reproduce Steps to reproduce the behavior:

• open a story and then close it
• you will see

The button for showing the legends still is there because the maps are loaded and in this case they contain legends

Expected behavior

• Clean up the map

[Maartenvm]

consolidated in #126