fixed problem with tooltips not always being displayed correctly

src/display.cpp

@@ -645,7 +645,7 @@ void display::draw_unit_details(int x, int y, const gamemap::location& loc,
 	if(teams_.empty())
 		return;
 
-	tooltips::clear_tooltips();
+	tooltips::clear_tooltips(description_rect);
 
 	SDL_Rect clipRect = clip_rect != NULL ? *clip_rect : screen_area();
 

src/tooltips.cpp

@@ -141,6 +141,20 @@ void clear_tooltips()
 	current_message = "";
 }
 
+void clear_tooltips(const SDL_Rect& rect)
+{
+	clear_tooltips();
+	for(std::vector<tooltip>::iterator i = tips.begin(); i != tips.end(); ) {
+		if(rectangles_overlap(i->rect,rect)) {
+			i = tips.erase(i);
+		} else {
+			++i;
+		}
+	}
+
+	current_message = "";
+}
+
 void add_tooltip(const SDL_Rect& rect, const std::string& message)
 {
 	for(std::vector<tooltip>::iterator i = tips.begin(); i != tips.end(); ++i) {

src/tooltips.hpp

@@ -15,6 +15,7 @@ struct manager
 };
 
 void clear_tooltips();
+void clear_tooltips(const SDL_Rect& rect);
 void add_tooltip(const SDL_Rect& rect, const std::string& message);
 void process(int mousex, int mousey, bool lbutton);