Improve handling of lost connection to openHAB

[eikowagenknecht]

The problem

When the connection to openHAB is lost the MainUI goes into a weird state where it seems like it's loading something but never finishes:

.. but this never stops, not even after minutes when OH is reachable again.

Your suggestion

When the connection is lost (e.g. timeout of 10s or something like that), replace the whole app screen with something that shows the user what the problem is, e.g.:

• "openHAB ist restarting. This will automatically refresh after it's up again." (auto refresh would need to be implemented then as well of course)
• (if we can't be this specific): "Connection lost. Reload this page to try again."

Your environment

OH 3.0.1

[thomaszlow]

I can confirm this issue in OH 3.0.1.

I'd like to add that in my case Crtl+R doesn't solve the issue, especially when several instances are open in several tabs. Only closing all tabs and opening OpenHab in a new tab solves the issue.