Binding development, howto remove a thing correctly?

I’m trying to work on the tankerkoening binding, which isn’t released to the offical binding list so far.

Removing a thing, from which a channel is linked to an item.

My Problem:
After the remove, the link is still there, and I’m geting log entries like:

2017-03-07 15:27:50.444 [WARN ] [ome.core.thing.internal.ThingManager] - Cannot delegate update ‘1.129’ for item ‘Diesel_1’ to handler for channel ‘tankerkoenig:tankstelle:978acd9c:diesel’, because no thing with the UID ‘tankerkoenig:tankstelle:978acd9c’ could be found.
@dolic Did you see this error?

The mentioned thing has been removed (so it can’t correctly be found). The item gets updated by a rule now, but why would the (String-)Item try update the channel when it recieves a change? Isn’t that the wrong way around?
Why is the link still there (rechecked with “smarthome:links”)? My dispose routine looks like that:
public void dispose() {
When trying to debug in Eclipse, I can’t get the same setup because running in debug-mode I can’t create the link from the thing-channnel to the (String-) Item??