Version 1.0.1 didn't have the Image Set Chooser, so you can use that one if you don't like it. If I make another version, I'll add a configuration file for options like showing the chooser.
Also, if you right click a Shimeji character itself and use the "Reduce to One" there (not through the tray icon), ONLY that type of Shimeji will reduce to one.
And if you accidentally use the tray icon "Reduce to one", you can actually can get the other shimeji types back. If you left click the tray icon, a random shimeji will fall. Eventually you'll get lucky