Explicitly return None for negative event indices. Prior to this,

eventat(-1) would return the next-to-last event causing the back button
to cycle back to the end of an event source instead of stopping at the
start.

1 files changed, 1 insertions, 1 deletions

diff --git a/tools/sched/schedgraph.py b/tools/sched/schedgraph.py
index 4335574..e592514 100644
--- a/tools/sched/schedgraph.py
+++ b/tools/sched/schedgraph.py
@@ -856,7 +856,7 @@ class EventSource:
 		return (Y_EVENTSOURCE)
 
 	def eventat(self, i):
-		if (i >= len(self.events)):
+		if (i >= len(self.events) or i < 0):
 			return (None)
 		event = self.events[i]
 		return (event)