Installed the demo today and I get the same behavior. I debugged the window size messages received from the plugin but I cannot make sense of it 😕
I tried changing the Podium code for handling plugin window sizing but got the same behavior. The first time the plugin window is opened it requests the host to sets its size to width=2 and height=26. Immediately after that comes a second request to set the window to its proper size. When the plugin editor has been closed and is reopened, only the first request for a size of 2×26 is sent. I hope you can live with the workaround.