--- a/src/widget.cpp
+++ b/src/widget.cpp
@@ -920,6 +920,13 @@
  */
 
 /**
+ * @fn void FillNestedArray(NWidgetCore **array, uint length)
+ * Fill the Window::nested_array array with pointers to nested widgets in the tree.
+ * @param array Base pointer of the array.
+ * @param length Length of the array.
+ */
+
+/**
  * Store size and position.
  * @param sizing         Type of resizing to perform.
  * @param x              Horizontal offset of the widget relative to the left edge of the window.
@@ -1080,6 +1087,11 @@
 	this->tool_tip = tool_tip;
 }
 
+void NWidgetCore::FillNestedArray(NWidgetCore **array, uint length)
+{
+	if (this->index >= 0 && (uint)(this->index) < length) array[this->index] = this;
+}
+
 void NWidgetCore::StoreWidgets(Widget *widgets, int length, bool left_moving, bool top_moving, bool rtl)
 {
 	if (this->index < 0) return;
@@ -1182,6 +1194,13 @@
 	}
 }
 
+void NWidgetContainer::FillNestedArray(NWidgetCore **array, uint length)
+{
+	for (NWidgetBase *child_wid = this->head; child_wid != NULL; child_wid = child_wid->next) {
+		child_wid->FillNestedArray(array, length);
+	}
+}
+
 /**
  * Return the biggest possible size of a nested widget.
  * @param base      Base size of the widget.
@@ -1604,6 +1623,10 @@
 	this->smallest_y = this->min_y;
 }
 
+void NWidgetSpacer::FillNestedArray(NWidgetCore **array, uint length)
+{
+}
+
 void NWidgetSpacer::StoreWidgets(Widget *widgets, int length, bool left_moving, bool top_moving, bool rtl)
 {
 	/* Spacer widgets are never stored in the widget array. */
@@ -1732,6 +1755,12 @@
 	if (this->child != NULL) this->child->StoreWidgets(widgets, length, left_moving, top_moving, rtl);
 }
 
+void NWidgetBackground::FillNestedArray(NWidgetCore **array, uint length)
+{
+	if (this->index >= 0 && (uint)(this->index) < length) array[this->index] = this;
+	if (this->child != NULL) this->child->FillNestedArray(array, length);
+}
+
 void NWidgetBackground::Draw(const Window *w)
 {
 	if (this->current_x == 0 || this->current_y == 0) return;

--- a/src/widget_type.h
+++ b/src/widget_type.h
@@ -181,6 +181,7 @@
 	virtual void AssignSizePosition(SizingType sizing, uint x, uint y, uint given_width, uint given_height, bool allow_resize_x, bool allow_resize_y, bool rtl) = 0;
 
 	virtual void StoreWidgets(Widget *widgets, int length, bool left_moving, bool top_moving, bool rtl) = 0;
+	virtual void FillNestedArray(NWidgetCore **array, uint length) = 0;
 
 	virtual NWidgetCore *GetWidgetFromPos(int x, int y) = 0;
 	virtual NWidgetBase *GetWidgetOfType(WidgetType tp);
@@ -296,6 +297,7 @@
 	inline bool IsDisabled();
 
 	void StoreWidgets(Widget *widgets, int length, bool left_moving, bool top_moving, bool rtl);
+	/* virtual */ void FillNestedArray(NWidgetCore **array, uint length);
 	/* virtual */ NWidgetCore *GetWidgetFromPos(int x, int y);
 
 	virtual Scrollbar *FindScrollbar(Window *w, bool allow_next = true) = 0;
@@ -346,6 +348,7 @@
 	~NWidgetContainer();
 
 	void Add(NWidgetBase *wid);
+	/* virtual */ void FillNestedArray(NWidgetCore **array, uint length);
 
 	/** Return whether the container is empty. */
 	inline bool IsEmpty() { return head == NULL; };
@@ -442,6 +445,7 @@
 
 	void SetupSmallestSize(Window *w, bool init_array);
 	void StoreWidgets(Widget *widgets, int length, bool left_moving, bool top_moving, bool rtl);
+	/* virtual */ void FillNestedArray(NWidgetCore **array, uint length);
 
 	/* virtual */ void Draw(const Window *w);
 	/* virtual */ void Invalidate(const Window *w) const;
@@ -462,6 +466,7 @@
 	void AssignSizePosition(SizingType sizing, uint x, uint y, uint given_width, uint given_height, bool allow_resize_x, bool allow_resize_y, bool rtl);
 
 	void StoreWidgets(Widget *widgets, int length, bool left_moving, bool top_moving, bool rtl);
+	/* virtual */ void FillNestedArray(NWidgetCore **array, uint length);
 
 	/* virtual */ void Draw(const Window *w);
 	/* virtual */ NWidgetCore *GetWidgetFromPos(int x, int y);