Bring sprites to front when they are being dragged.

This solves the issue where in both player and editor mode, draggable sprites would not get popped to the front of the draw list.

src/containers/stage.jsx

@@ -309,11 +309,13 @@ class Stage extends React.Component {
         const targetId = this.props.vm.getTargetIdForDrawableId(drawableId);
         if (targetId === null) return;
 
-        // Only start drags on non-draggable targets in editor drag mode
-        if (!this.props.useEditorDragStyle) {
-            const target = this.props.vm.runtime.getTargetById(targetId);
-            if (!target.draggable) return;
-        }
+        const target = this.props.vm.runtime.getTargetById(targetId);
+
+        // Do not start drag unless in editor drag mode or target is draggable
+        if (!(this.props.useEditorDragStyle || target.draggable)) return;
+
+        // Dragging always brings the target to the front
+        target.goToFront();
 
         this.props.vm.startDrag(targetId);
         this.setState({