diff --git a/src/app/doc_exporter.cpp b/src/app/doc_exporter.cpp
index 571e761a7..6b49ef2d0 100644
--- a/src/app/doc_exporter.cpp
+++ b/src/app/doc_exporter.cpp
@@ -376,14 +376,14 @@ public:
     else
       pr.pack(gfx::Size(width, height));
 
-    auto it = samples.begin();
-    for (auto& rc : pr) {
-      if (it->isDuplicated())
+    auto it = pr.begin();
+    for (auto& sample : samples) {
+      if (sample.isDuplicated() ||
+          sample.isEmpty())
         continue;
 
-      ASSERT(it != samples.end());
-      it->setInTextureBounds(rc);
-      ++it;
+      ASSERT(it != pr.end());
+      sample.setInTextureBounds(*(it++));
     }
   }
 };