Finishing SMask at the end of operators list.

src/display/canvas.js

@@ -870,6 +870,11 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
     },
 
     endDrawing: function CanvasGraphics_endDrawing() {
+      // Finishing all opened operations such as SMask group painting.
+      if (this.current.activeSMask !== null) {
+        this.endSMaskGroup();
+      }
+
       this.ctx.restore();
 
       if (this.transparentCanvas) {