Index: trunk/src/hid_helper.c
===================================================================
--- trunk/src/hid_helper.c	(revision 18236)
+++ trunk/src/hid_helper.c	(revision 18237)
@@ -245,8 +245,11 @@
 
 void pcb_cam_end(pcb_cam_t *dst)
 {
+	free(dst->inst);
+	dst->inst = NULL;
+	if (!dst->active)
+		return;
 	layervis_restore(dst);
-	free(dst->inst);
 	dst->active = 0;
 }