(svn r18675) -Add [FS#3256]: function to remove focus from all widgets in a window

src/window.cpp

@@ -132,6 +132,18 @@ bool EditBoxInGlobalFocus()
 	return _focused_window->nested_focus != NULL && _focused_window->nested_focus->type == WWT_EDITBOX;
 }
 
+/**
+ * Makes no widget on this window have focus. The function however doesn't change which window has focus.
+ */
+void Window::UnfocusFocusedWidget()
+{
+	if (this->nested_focus != NULL) {
+		/* Repaint the widget that lost focus. A focused edit box may else leave the caret on the screen. */
+		this->nested_focus->SetDirty(this);
+		this->nested_focus = NULL;
+	}
+}
+
 /**
  * Set focus within this window to the given widget. The function however doesn't change which window has focus.
  * @param widget_index Index of the widget in the window to set the focus to.

src/window_gui.h

@@ -519,6 +519,7 @@ public:
 		return this->GetWidget<NWidgetCore>(widget_index)->IsLowered();
 	}
 
+	void UnfocusFocusedWidget();
 	bool SetFocusedWidget(byte widget_index);
 
 	void HandleButtonClick(byte widget);