Fixed the assertion failure with long options.

This fixes bug #12970.

I also found a new development plan

- commit silly bugs that cause assertion failures.

- get bribed with cookies to fix it.

- ...

- Cookies :-)

changelog

@@ -31,6 +31,7 @@
  * User interface:
    * Fixed an exception when certain characters weren't escaped
    * Removed the gamma correction option (code is only disabled not removed)
+   * Fixed the assertion failure with long options (bug #12970)
  * WML Engine
    * [replace_map] changes the map completely, changing the map size is 
      posible - off-map units go into the recall list
@@ -7972,4 +7973,4 @@ Version 0.2.1:
  * infinite recall bug fixed
  * recalling now costs 20 gold pieces. Gold from previous scenarios carries over,
    and there is a bonus for finishing a scenario early
- * better transitions between tiles added (graphics for this not complete though)
+ * better transitions between tiles added (graphics for this not complete though)

players_changelog

@@ -27,6 +27,7 @@ Version 1.5.9+svn:
 
   * User interface
     * Removed the gamma correction option.
+    * Fixed the problem that some dialogs terminated Wesnoth.
 
 Version 1.5.9:
   * Campaigns

src/gui/widgets/grid.cpp

@@ -1098,9 +1098,9 @@ unsigned tgrid::column_use_horizontal_scrollbar(
 		const tpoint size(cell.get_best_size());
 
 		if(required_width == 0
-				|| static_cast<size_t>(size.y) > required_width) {
+				|| static_cast<size_t>(size.x) > required_width) {
 
-			required_width = size.y;
+			required_width = size.x;
 		}
 	}