Aaaand a bugfix (Synth1 1.10) has been released. Note that in the new version, you cannot browse patches from OpenMPT (or any other host) anymore by default, because it caused problems as it seems. You have to enable the "select program from host" option (registry write access necessary, so you might have to run OpenMPT as administrator) and reload the plugin to browse patches using OpenMPT's preset navgiator again.