Config Tab is misbevahin'

[dnmeid]

Describe the bug
After startup of companion the config tab is not visible.
The tab gets visible when adding an instance.
The tab points to the instance which was configured last, even if the instance has been deleted in between.

To Reproduce
Steps to reproduce the behavior:

1. Start companion: no tab
2. Add instance: tab shows up
3. Delete instance: tab still configures deleted instance

Expected behavior
The tab should only be visible when configuring an instance either after creation or after Edit clicked (Edit should be named Config). When switching to a different tab the config tab should dissapear.

Desktop (please complete the following information):

• OS: OSX 10.12
• Browser Firefox
• Version 60