tlaplus: Toolbox has rendering problems and crashes often on Gnome with GDK_SCALE

Hello, I tried both the 1.7.1 release and 1.8.0 release on an up to date Pop!_OS 21.04 (which is basically Ubuntu 21.04 from what I understand) and I get what you can see on the screenshot in both cases. Moreover, the toolbox often crashes with the following error, which makes it pretty much unusable.

(TLA+ Toolbox:11813): Gdk-ERROR **: 08:38:00.567: The program 'TLA+ Toolbox' received an X Window System error.
This probably reflects a bug in the program.
The error was 'BadAlloc (insufficient resources for operation)'.
  (Details: serial 9788727 error_code 11 request_code 130 (MIT-SHM) minor_code 5)
  (Note to programmers: normally, X errors are reported asynchronously;
   that is, you will receive the error a while after causing it.
   To debug your program, run it with the GDK_SYNCHRONIZE environment
   variable to change this behavior. You can then get a meaningful
   backtrace from your debugger if you break on the gdk_x_error() function.)

I also get a lot of:

(TLA+ Toolbox:11813): Gtk-CRITICAL **: 08:36:36.688: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GtkScrollbar