window hangin after it is closed

[plampite]

For some still unknown reason, when the interaction window is closed it doesn't actually close (yet it is impossible to interact with it anymore).

The server will keep working and a new interaction can be started from the client, but this will hang as well once terminated, and so on.

Only when the server is shutdown will all the open interaction windows actually close.

There seems to be no leak, so it's unclear now what may be the cause.

But this bug doesn't defeat the main purpose of the program, which is illustrative.