diff -r f531819ae921 src/genworld_gui.cpp
--- a/src/genworld_gui.cpp	Wed May 19 17:04:02 2010 +0000
+++ b/src/genworld_gui.cpp	Thu May 20 22:18:36 2010 +0200
@@ -362,6 +362,13 @@
 		this->caption = STR_NULL;
 		this->afilter = CS_NUMERAL;
 
+		/* Disable town, industry and trees in SE */
+		this->SetWidgetDisabledState(GLAND_TOWN_PULLDOWN,     _game_mode == GM_EDITOR);
+		this->SetWidgetDisabledState(GLAND_INDUSTRY_PULLDOWN, _game_mode == GM_EDITOR);
+		this->SetWidgetDisabledState(GLAND_TREE_PULLDOWN,     _game_mode == GM_EDITOR);
+
+		UpdateWidgetStatus();
+
 		this->mode = (GenenerateLandscapeWindowMode)this->window_number;
 	}
 
@@ -400,6 +407,36 @@
 		}
 	}
 
+	virtual void UpdateWidgetStatus() {
+		/* Disable snowline if not arctic */
+		this->SetWidgetDisabledState(GLAND_SNOW_LEVEL_TEXT, _settings_newgame.game_creation.landscape != LT_ARCTIC);
+		this->SetWidgetDisabledState(GLAND_SNOW_LEVEL_DOWN, _settings_newgame.game_creation.snow_line_height <= MIN_SNOWLINE_HEIGHT || _settings_newgame.game_creation.landscape != LT_ARCTIC);
+		this->SetWidgetDisabledState(GLAND_SNOW_LEVEL_UP,   _settings_newgame.game_creation.snow_line_height >= MAX_SNOWLINE_HEIGHT || _settings_newgame.game_creation.landscape != LT_ARCTIC);
+
+		/* Disable date up / down buttons, if at limit */
+		this->SetWidgetDisabledState(GLAND_START_DATE_DOWN, _settings_newgame.game_creation.starting_year <= MIN_YEAR);
+		this->SetWidgetDisabledState(GLAND_START_DATE_UP,   _settings_newgame.game_creation.starting_year >= MAX_YEAR);
+
+		/* You can't select smoothness / non-water borders if not terragenesis */
+		if (mode == GLWM_GENERATE) {
+			this->SetWidgetDisabledState(GLAND_SMOOTHNESS_PULLDOWN, _settings_newgame.game_creation.land_generator == 0);
+			this->SetWidgetDisabledState(GLAND_VARIETY_PULLDOWN, _settings_newgame.game_creation.land_generator == 0);
+			this->SetWidgetDisabledState(GLAND_BORDERS_RANDOM, _settings_newgame.game_creation.land_generator == 0 || !_settings_newgame.construction.freeform_edges);
+			this->SetWidgetsDisabledState(_settings_newgame.game_creation.land_generator == 0 || !_settings_newgame.construction.freeform_edges || _settings_newgame.game_creation.water_borders == BORDERS_RANDOM,
+					GLAND_WATER_NW, GLAND_WATER_NE, GLAND_WATER_SE, GLAND_WATER_SW, WIDGET_LIST_END);
+
+			this->SetWidgetLoweredState(GLAND_BORDERS_RANDOM, _settings_newgame.game_creation.water_borders == BORDERS_RANDOM);
+
+			this->SetWidgetLoweredState(GLAND_WATER_NW, HasBit(_settings_newgame.game_creation.water_borders, BORDER_NW));
+			this->SetWidgetLoweredState(GLAND_WATER_NE, HasBit(_settings_newgame.game_creation.water_borders, BORDER_NE));
+			this->SetWidgetLoweredState(GLAND_WATER_SE, HasBit(_settings_newgame.game_creation.water_borders, BORDER_SE));
+			this->SetWidgetLoweredState(GLAND_WATER_SW, HasBit(_settings_newgame.game_creation.water_borders, BORDER_SW));
+
+			this->SetWidgetsDisabledState(_settings_newgame.game_creation.land_generator == 0 && (_settings_newgame.game_creation.landscape == LT_ARCTIC || _settings_newgame.game_creation.landscape == LT_TROPIC),
+					GLAND_TERRAIN_PULLDOWN, GLAND_WATER_PULLDOWN, WIDGET_LIST_END);
+		}
+	}
+
 	virtual void UpdateWidgetSize(int widget, Dimension *size, const Dimension &padding, Dimension *fill, Dimension *resize)
 	{
 		const StringID *strs = NULL;
@@ -479,43 +516,7 @@
 
 	virtual void OnPaint()
 	{
-		/* You can't select smoothness / non-water borders if not terragenesis */
-		if (mode == GLWM_GENERATE) {
-			this->SetWidgetDisabledState(GLAND_SMOOTHNESS_PULLDOWN, _settings_newgame.game_creation.land_generator == 0);
-			this->SetWidgetDisabledState(GLAND_VARIETY_PULLDOWN, _settings_newgame.game_creation.land_generator == 0);
-			this->SetWidgetDisabledState(GLAND_BORDERS_RANDOM, _settings_newgame.game_creation.land_generator == 0 || !_settings_newgame.construction.freeform_edges);
-			this->SetWidgetsDisabledState(_settings_newgame.game_creation.land_generator == 0 || !_settings_newgame.construction.freeform_edges || _settings_newgame.game_creation.water_borders == BORDERS_RANDOM,
-					GLAND_WATER_NW, GLAND_WATER_NE, GLAND_WATER_SE, GLAND_WATER_SW, WIDGET_LIST_END);
-
-			this->SetWidgetLoweredState(GLAND_BORDERS_RANDOM, _settings_newgame.game_creation.water_borders == BORDERS_RANDOM);
-
-			this->SetWidgetLoweredState(GLAND_WATER_NW, HasBit(_settings_newgame.game_creation.water_borders, BORDER_NW));
-			this->SetWidgetLoweredState(GLAND_WATER_NE, HasBit(_settings_newgame.game_creation.water_borders, BORDER_NE));
-			this->SetWidgetLoweredState(GLAND_WATER_SE, HasBit(_settings_newgame.game_creation.water_borders, BORDER_SE));
-			this->SetWidgetLoweredState(GLAND_WATER_SW, HasBit(_settings_newgame.game_creation.water_borders, BORDER_SW));
-
-			this->SetWidgetsDisabledState(_settings_newgame.game_creation.land_generator == 0 && (_settings_newgame.game_creation.landscape == LT_ARCTIC || _settings_newgame.game_creation.landscape == LT_TROPIC),
-					GLAND_TERRAIN_PULLDOWN, GLAND_WATER_PULLDOWN, WIDGET_LIST_END);
-		}
-		/* Disable snowline if not hilly */
-		this->SetWidgetDisabledState(GLAND_SNOW_LEVEL_TEXT, _settings_newgame.game_creation.landscape != LT_ARCTIC);
-		/* Disable town, industry and trees in SE */
-		this->SetWidgetDisabledState(GLAND_TOWN_PULLDOWN,     _game_mode == GM_EDITOR);
-		this->SetWidgetDisabledState(GLAND_INDUSTRY_PULLDOWN, _game_mode == GM_EDITOR);
-		this->SetWidgetDisabledState(GLAND_TREE_PULLDOWN,     _game_mode == GM_EDITOR);
-
-		this->SetWidgetDisabledState(GLAND_START_DATE_DOWN, _settings_newgame.game_creation.starting_year <= MIN_YEAR);
-		this->SetWidgetDisabledState(GLAND_START_DATE_UP,   _settings_newgame.game_creation.starting_year >= MAX_YEAR);
-		this->SetWidgetDisabledState(GLAND_SNOW_LEVEL_DOWN, _settings_newgame.game_creation.snow_line_height <= MIN_SNOWLINE_HEIGHT || _settings_newgame.game_creation.landscape != LT_ARCTIC);
-		this->SetWidgetDisabledState(GLAND_SNOW_LEVEL_UP,   _settings_newgame.game_creation.snow_line_height >= MAX_SNOWLINE_HEIGHT || _settings_newgame.game_creation.landscape != LT_ARCTIC);
-
-		this->SetWidgetLoweredState(GLAND_TEMPERATE, _settings_newgame.game_creation.landscape == LT_TEMPERATE);
-		this->SetWidgetLoweredState(GLAND_ARCTIC,    _settings_newgame.game_creation.landscape == LT_ARCTIC);
-		this->SetWidgetLoweredState(GLAND_TROPICAL,  _settings_newgame.game_creation.landscape == LT_TROPIC);
-		this->SetWidgetLoweredState(GLAND_TOYLAND,   _settings_newgame.game_creation.landscape == LT_TOYLAND);
-
 		this->DrawWidgets();
-
 		this->DrawEditBox(GLAND_RANDOM_EDITBOX);
 	}
 
@@ -528,6 +529,12 @@
 			case GLAND_TOYLAND:
 				this->RaiseWidget(_settings_newgame.game_creation.landscape + GLAND_TEMPERATE);
 				SetNewLandscapeType(widget - GLAND_TEMPERATE);
+				this->SetWidgetLoweredState(GLAND_TEMPERATE, _settings_newgame.game_creation.landscape == LT_TEMPERATE);
+				this->SetWidgetLoweredState(GLAND_ARCTIC,    _settings_newgame.game_creation.landscape == LT_ARCTIC);
+				this->SetWidgetLoweredState(GLAND_TROPICAL,  _settings_newgame.game_creation.landscape == LT_TROPIC);
+				this->SetWidgetLoweredState(GLAND_TOYLAND,   _settings_newgame.game_creation.landscape == LT_TOYLAND);
+
+				UpdateWidgetStatus();
 				break;
 
 			case GLAND_MAPSIZE_X_PULLDOWN: // Mapsize X
@@ -580,6 +587,7 @@
 
 					_settings_newgame.game_creation.starting_year = Clamp(_settings_newgame.game_creation.starting_year + widget - GLAND_START_DATE_TEXT, MIN_YEAR, MAX_YEAR);
 				}
+				UpdateWidgetStatus();
 				_left_button_clicked = false;
 				break;
 
@@ -587,6 +595,7 @@
 				this->widget_id = GLAND_START_DATE_TEXT;
 				SetDParam(0, _settings_newgame.game_creation.starting_year);
 				ShowQueryString(STR_JUST_INT, STR_MAPGEN_START_DATE_QUERY_CAPT, 8, 100, this, CS_NUMERAL, QSF_ENABLE_DEFAULT);
+				UpdateWidgetStatus();
 				break;
 
 			case GLAND_SNOW_LEVEL_DOWN:
@@ -597,7 +606,8 @@
 					this->SetDirty();
 
 					_settings_newgame.game_creation.snow_line_height = Clamp(_settings_newgame.game_creation.snow_line_height + widget - GLAND_SNOW_LEVEL_TEXT, MIN_SNOWLINE_HEIGHT, MAX_SNOWLINE_HEIGHT);
-				}
+					UpdateWidgetStatus();
+					}
 				_left_button_clicked = false;
 				break;
 
@@ -613,6 +623,7 @@
 
 			case GLAND_LANDSCAPE_PULLDOWN: // Landscape generator
 				ShowDropDownMenu(this, _landscape, _settings_newgame.game_creation.land_generator, GLAND_LANDSCAPE_PULLDOWN, 0, 0);
+				UpdateWidgetStatus();
 				break;
 
 			case GLAND_HEIGHTMAP_ROTATION_PULLDOWN: // Heightmap rotation
@@ -695,8 +706,11 @@
 			case GLAND_TREE_PULLDOWN:          _settings_newgame.game_creation.tree_placer = index; break;
 			case GLAND_SMOOTHNESS_PULLDOWN:    _settings_newgame.game_creation.tgen_smoothness = index;  break;
 			case GLAND_VARIETY_PULLDOWN:       _settings_newgame.game_creation.variety = index; break;
-			case GLAND_LANDSCAPE_PULLDOWN:     _settings_newgame.game_creation.land_generator = index; break;
 			case GLAND_HEIGHTMAP_ROTATION_PULLDOWN: _settings_newgame.game_creation.heightmap_rotation = index; break;
+			case GLAND_LANDSCAPE_PULLDOWN:
+				_settings_newgame.game_creation.land_generator = index;
+				UpdateWidgetStatus();
+				break;
 
 			case GLAND_TOWN_PULLDOWN:
 				if ((uint)index == CUSTOM_TOWN_NUMBER_DIFFICULTY) {
@@ -751,11 +765,13 @@
 			case GLAND_START_DATE_TEXT:
 				this->SetWidgetDirty(GLAND_START_DATE_TEXT);
 				_settings_newgame.game_creation.starting_year = Clamp(value, MIN_YEAR, MAX_YEAR);
+				UpdateWidgetStatus();
 				break;
 
 			case GLAND_SNOW_LEVEL_TEXT:
 				this->SetWidgetDirty(GLAND_SNOW_LEVEL_TEXT);
 				_settings_newgame.game_creation.snow_line_height = Clamp(value, MIN_SNOWLINE_HEIGHT, MAX_SNOWLINE_HEIGHT);
+				UpdateWidgetStatus();
 				break;
 
 			case GLAND_TOWN_PULLDOWN: