Index: src/document.cpp
===================================================================
--- src/document.cpp	(revision 19897)
+++ src/document.cpp	(working copy)
@@ -552,10 +552,19 @@
     double const h = rect.height();
 
     double const old_height = sp_document_height(this);
+    double const old_width = sp_document_width(this);
+    SPRoot *root = SP_ROOT(this->root);
     SPUnit const &px(sp_unit_get_by_id(SP_UNIT_PX));
     sp_document_set_width(this, w, &px);
     sp_document_set_height(this, h, &px);
 
+    /* Modify viewbox to fit in with new height/width */
+    if (root->viewBox_set){
+        root->viewBox.x0 = root->viewBox.x0 * (w / old_width);
+        root->viewBox.x1 = root->viewBox.x1 * (w / old_width);
+        root->viewBox.y0 = root->viewBox.y0 * (h / old_height);
+        root->viewBox.y1 = root->viewBox.y1 * (h / old_height);
+    }
     Geom::Translate const tr(Geom::Point(0, (old_height - h))
                              - to_2geom(rect.min()));
     SP_GROUP(root)->translateChildItems(tr);