opening lv2 gui multiple times crashes host

[devloop0123]

Tested in MusE, Qtractor, and Carla, on Linux Mint 21.3, with SFizz-ui built from source.

Opening an SFizz LV2 GUI multiple times in a row, will corrupt the GUI (usually after ~2-10 times), and crash not long after.

Curiously, keeping a dummy SFizz GUI open, while opening/closing another, seems to prevent the above behaviour.

MusE gives this error:

muse4: ../../../../src/cairo-xcb-screen.c:219: _get_screen_index: Assertion `!"reached"' failed.
Aborted (core dumped)

I only have a single monitor btw

[audio2000]

I reported this as well on the other Github page, just made the assumption that sfizz-gui was going to be for the adding of GUI graphical capabilities to SFZ instruments, did not realize, until I read further into it, I apologize. I have experienced this as well and maybe can add some more information not mentioned. I will copy the post I made below.

Linux / Debian Based
Sfizz 1.2.3 LV2 & VST3 versions from official website

Not the best time to discover this when this project does not appear to be being developed any longer, but I noticed the following issue. When this plugin is inserted into a Linux based application and the GUI window is opened and closed a few times it crashes/closes the application it is running instantly.
-This happens mainly in the LV2 version, I thought I experience this before in the VST3 but harder to reproduce.
-Tested this in Carla & Ardour and happens in both applications.
-Experienced this with or without an instrument loaded.
-Sometimes I will notice the GUI starts to only show the keyboard graphic at the bottom of the window but the rest will either be blank background color or black boxes where other GUI items would appear.
Probably just coincidence but I have noticed that if I create one track with LV2 version and one track with VST3 version, when I open and close the LV2 in this case I cannot really generate the instant close issue, but this seems to make this LV2 graphical issues occur more so.
-I would say noticed this occurring after no less than three open and close
-Do not notice any high CPU issues or high RAM uses either.

Hopefully some of this will be helpful as well.
Thank You

EDIT:
Not sure if this has any relation with the following issue #144 because this was also noticed in the LV2 version and not the VST3 version.