On Windows Server 2019, verion 1809, build 17763.7009, running in Desktop mode. I've just upgraded from pgAdmin 9.1 to 9.2. I open it, connect to a database, and try to open the query tool. This can be either using the icon on the toolbar, right-clicking on the database and selecting the Query Tool menu option, or using Alt-Shift-Q. There is a brief flash where it looks like the query tool is trying to open, then the pane goes blank and stays that way. The resulting tabs then refuse to close.