tlistbox: move header and footer grids out of main grid (workaround f…

…or bug #23752)

This isn't a perfect solution, as it renders horizontal scrollbars incapable of
affecting either. However, I'm working on the assumption that most listbox uses
have (or should have) horizontal_scrollbar_mode = "never" in their WML.

data/gui/default/widget/listbox_default.cfg

@@ -41,30 +41,38 @@
 		[grid]
 
 			[row]
-				grow_factor = 1
+				grow_factor = 0
 
 				[column]
 					grow_factor = 1
-								horizontal_grow = "true" # needed ?
-								vertical_grow = "true" # needed ?
+					horizontal_grow = "true"
+					vertical_alignment = "top"
 
 					[grid]
-						id = "_content_grid"
+						id = "_header_grid"
+					[/grid]
 
-						[row]
-							grow_factor = 1
+				[/column]
 
-							[column]
-								grow_factor = 1
-								horizontal_grow = "true"
+				[column]
 
-								[grid]
-									id = "_header_grid"
-								[/grid]
+					[spacer]
+					[/spacer]
 
-							[/column]
+				[/column]
 
-						[/row]
+			[/row]
+
+			[row]
+				grow_factor = 1
+
+				[column]
+					grow_factor = 1
+					horizontal_grow = "true" # needed ?
+					vertical_grow = "true" # needed ?
+
+					[grid]
+						id = "_content_grid"
 
 						[row]
 
@@ -80,27 +88,37 @@
 
 						[/row]
 
-						[row]
+					[/grid]
 
-							[column]
-								horizontal_grow = "true"
+				[/column]
 
-								[grid]
-									id = "_footer_grid"
-								[/grid]
+				[column]
+					grow_factor = 0
 
-							[/column]
+					{GUI__VERTICAL_SCROLLBAR_GRID}
 
-						[/row]
+				[/column]
 
+			[/row]
+
+			[row]
+				grow_factor = 0
+
+				[column]
+					grow_factor = 1
+					horizontal_grow = "true"
+					vertical_alignment = "bottom"
+
+					[grid]
+						id = "_footer_grid"
 					[/grid]
 
 				[/column]
 
 				[column]
-					grow_factor = 0
 
-					{GUI__VERTICAL_SCROLLBAR_GRID}
+					[spacer]
+					[/spacer]
 
 				[/column]