Make the restore of the window background conditionally.

src/gui/dialogs/dialog.cpp

@@ -45,7 +45,7 @@ void tdialog::show(CVideo& video)
 
 	pre_show(video, window);
 
-	retval_ = window.show(true);
+	retval_ = window.show(restore_);
 
 	if(retval_ ==  twindow::OK) {
 		finalize_fields(window);

src/gui/dialogs/dialog.hpp

@@ -37,7 +37,8 @@ class tdialog
 public:
 	tdialog() : 
 		retval_(0),
-		fields_()
+		fields_(),
+		restore_(true)
 	{}
 
 	virtual ~tdialog();
@@ -45,8 +46,12 @@ public:
 	/** Shows the window */
 	void show(CVideo& video);
 
+	/***** ***** ***** setters / getters for members ***** ****** *****/
+
 	int get_retval() const { return retval_; }
 
+	void set_restore(const bool restore) { restore_ = restore; }
+
 protected:
 
 	/**
@@ -106,6 +111,15 @@ private:
 	 */
 	std::vector<tfield_*> fields_;
 
+	/** 
+	 * Restore the screen after showing?
+	 *
+	 * Most windows should restore the display after showing so this value
+	 * defaults to true. Toplevel windows (like the titlescreen don't want this
+	 * behaviour so they can change it in pre_show().
+	 */
+	bool restore_;
+
 	/**
 	 * Builds the window.
 	 *