Only call idle() when the last stream closes

Author: gexgd0419

source/synthDrivers/sapi5.py

@@ -201,7 +201,9 @@ def EndStream(self, streamNum: int, pos: int):
 		synth.sonicStream.flush()
 		audioData = synth.sonicStream.readShort()
 		synth.player.feed(audioData, len(audioData) * 2)
-		synth.player.idle()
+		if len(synth._streamBookmarks) == 1:
+			# This is the last closing stream. Safe to call idle().
+			synth.player.idle()
 		# trigger all untriggered bookmarks
 		if streamNum in synth._streamBookmarks:
 			for bookmark in synth._streamBookmarks[streamNum]: