diff --git a/src/evdev-mt-touchpad-thumb.c b/src/evdev-mt-touchpad-thumb.c
index b5ce2998..4d9b6f26 100644
--- a/src/evdev-mt-touchpad-thumb.c
+++ b/src/evdev-mt-touchpad-thumb.c
@@ -158,6 +158,8 @@ tp_init_thumb(struct tp_dispatch *tp)
 	struct quirks_context *quirks;
 	struct quirks *q;
 
+	tp->thumb.detect_thumbs = false;
+
 	if (!tp->buttons.is_clickpad)
 		return;