prevent multiple YASGUI instances/browser tab usage to not have data loss

[JJ-Author]

It would be useful to prevent using multiple instances (maybe also with a client side setting only) of YASGUI in the same browser instance (tabs/windows). I experienced data loss for my "query tabs" and query modifications due to multiple yasgui instances opened with different states (e.g. a different set of "query tabs" opened). Since I receive plenty yasgui links i usually have more than one yasgui "instance" running, and accidently pick different ones to continue working. I would suggest whenever you open a new yasgui instance all the other one should be disabled.
maybe this could do the trick https://stackoverflow.com/a/59372368

another option to tackle the data loss would be to have a dedicated browser-storage object (YASGUI as a SPARQL IDE with "projects"). for every new instance. but i think this could get really messy very fast and a feature to move "yasgui tabs" to another session would be needed.