>> I'm not sure if this is intended, or if what I'm doing is allowed, but I
>> noticed that after I add an association to the current tab and then use
>> tab-switch twice, to change tab and then change back, the association I
>> added is gone.
>
> So you want to add more metadata to a tab?
> Once in the past I proposed such a feature,
> but no one needed it :)  Now this could be added.

Here is a patch that implements this, but it's still 100% untested,
so use it at your own risk :)