(svn r18932) -Codechange: Don't constantly redraw drop drop list.

src/widgets/dropdown.cpp

@@ -260,10 +260,17 @@ struct DropdownWindow : Window {
 
 	virtual void OnTick()
 	{
+		if (this->scrolling != 0) {
+			int pos = this->vscroll.GetPosition();
+
 			this->vscroll.UpdatePosition(this->scrolling);
 			this->scrolling = 0;
+
+			if (pos != this->vscroll.GetPosition()) {
 				this->SetDirty();
 			}
+		}
+	}
 
 	virtual void OnMouseLoop()
 	{
@@ -310,10 +317,12 @@ struct DropdownWindow : Window {
 				if (!this->GetDropDownItem(item)) return;
 			}
 
+			if (this->selected_index != item) {
 				this->selected_index = item;
 				this->SetDirty();
 			}
 		}
+	}
 };
 
 void ShowDropDownList(Window *w, DropDownList *list, int selected, int button, uint width, bool auto_width, bool instant_close)