Add support for horizontal scroll wheel. (Bjorn Winckler)
diff --git a/src/eval.c b/src/eval.c
index 4f1be3f..ac0ad26 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -10927,6 +10927,8 @@
 		|| n == K_X2MOUSE
 		|| n == K_X2DRAG
 		|| n == K_X2RELEASE
+		|| n == K_MOUSELEFT
+		|| n == K_MOUSERIGHT
 		|| n == K_MOUSEDOWN
 		|| n == K_MOUSEUP)
 	{