PortAudio API List Grows

Version 2.0.0 nightly revision 63fe67a, Windows 7.

The drop-down list of PortAudio APIs (I/O tab of Preferences) seems to be repopulated each time the preferences dialog box is opened, without ever being cleared. This results in an ever-growing list of duplicate entries. To reproduce, open and close the preferences dialog (I/O tab) a few times and inspect the drop-down list of APIs.