Hypnotix tv window won't close

[gurpal2000]

Distribution

Mint 21.3

Package version

6.0.4

Graphics hardware in use

Red Hat, Inc. QXL paravirtual graphic card

Frequency

Always

Bug description

Unable to close a tv window related to Hypnotix (eg. closing a channel window). If close the parent window, it disappears.

Steps to reproduce

1. Open a channel in Hypnotix, it works.
2. Try to close the "mpv" window (looks like a Python icon on the taskbar). The child window will freeze and refuse to disappear.

Expected behavior

1. The tv window should close, leaving the main window.
2. If I close any window in Mint, it should close or at least present a force kill option after a timeout. Isn't that a default anyway?

Additional information

It may be useful to know that this is a Mint VM deployed on Proxmox VE using the SPICE (qxl) driver.
Why that would matter I have no idea (it shouldn't matter at all).
Is there a way to NOT use mpv and something else say?