diff -r f895bf254aa0 src/genworld_gui.cpp
--- a/src/genworld_gui.cpp	Wed May 19 06:15:47 2010 +0200
+++ b/src/genworld_gui.cpp	Wed May 19 09:25:34 2010 +0200
@@ -182,7 +182,7 @@
 										NWidget(WWT_TEXT, COLOUR_ORANGE), SetDataTip(STR_MAPGEN_HEIGHTMAP_SIZE_LABEL, STR_NULL), SetFill(1, 1),
 									EndContainer(),
 									NWidget(NWID_VERTICAL, NC_EQUALSIZE), SetPIP(0, 4, 0),
-										NWidget(WWT_TEXT, COLOUR_ORANGE, GLAND_HEIGHTMAP_SIZE_TEXT), SetDataTip(STR_MAPGEN_HEIGHTMAP_SIZE, STR_NULL), SetFill(1, 0),
+										NWidget(WWT_TEXT, COLOUR_ORANGE, GLAND_HEIGHTMAP_SIZE_TEXT), SetDataTip(STR_MAPGEN_HEIGHTMAP_SIZE, STR_NULL), SetFill(1, 1),
 									EndContainer(),
 								EndContainer(),
 								NWidget(NWID_HORIZONTAL, NC_EQUALSIZE), SetPIP(0, 3, 0),
@@ -431,7 +431,7 @@
 		this->active_tab = SELPLANE_MAP;
 
 		this->mode = (GenenerateLandscapeWindowMode)this->window_number;
-		this->landscape_source = ((mode == GLWM_HEIGHTMAP) ? USE_HEIGHTMAP : (_settings_newgame.game_creation.land_generator == 0 ? USE_ORIGINAL : USE_TERRAGENESIS));
+		SetPlane(GLAND_TERRAIN_SOURCE, &this->landscape_source, (mode == GLWM_HEIGHTMAP) ? USE_HEIGHTMAP : (_settings_newgame.game_creation.land_generator == 0 ? USE_ORIGINAL : USE_TERRAGENESIS));
 	}
 
 
@@ -546,18 +546,6 @@
 
 	virtual void OnPaint()
 	{
-		NWidgetStacked *wi = this->GetWidget<NWidgetStacked>(GLAND_TAB);
-		if (this->active_tab != wi->shown_plane) {
-			wi->SetDisplayedPlane(this->active_tab);
-			this->SetDirty();
-			return;
-		}
-		wi = this->GetWidget<NWidgetStacked>(GLAND_TERRAIN_SOURCE);
-		if (this->landscape_source != wi->shown_plane) {
-			wi->SetDisplayedPlane(this->landscape_source);
-			this->SetDirty();
-			return;
-		}
 		this->SetWidgetLoweredState(GLAND_USE_HEIGHTMAP_BUTTON, this->landscape_source == USE_HEIGHTMAP);
 		this->SetWidgetLoweredState(GLAND_USE_ORIGINAL_BUTTON, this->landscape_source == USE_ORIGINAL);
 		this->SetWidgetLoweredState(GLAND_USE_TERRAGENESIS_BUTTON, this->landscape_source == USE_TERRAGENESIS);
@@ -604,6 +592,17 @@
 
 	}
 
+	virtual void SetPlane(int widget, int *plane, int sub_plane)
+	{
+		*plane = sub_plane;
+		NWidgetStacked *wi = this->GetWidget<NWidgetStacked>(widget);
+		if (*plane != wi->shown_plane) {
+			wi->SetDisplayedPlane(*plane);
+			this->SetDirty();
+			return;
+		}
+	}
+
 	virtual void OnClick(Point pt, int widget, int click_count)
 	{
 		switch (widget) {
@@ -617,27 +616,22 @@
 				ShowSaveLoadDialog(SLD_LOAD_HEIGHTMAP);
 				if (_file_to_saveload.mode == SL_INVALID) break;
 				mode = GLWM_HEIGHTMAP;
-				this->landscape_source = USE_HEIGHTMAP;
-				Window::SetDirty();
+				SetPlane(GLAND_TERRAIN_SOURCE, &this->landscape_source, USE_HEIGHTMAP);
 				break;
 			case GLAND_USE_TERRAGENESIS_BUTTON:
 				mode = GLWM_GENERATE;
-				this->landscape_source = USE_TERRAGENESIS;
-				Window::SetDirty();
+				SetPlane(GLAND_TERRAIN_SOURCE, &this->landscape_source, USE_TERRAGENESIS);
 				break;
 			case GLAND_USE_ORIGINAL_BUTTON:
 				mode = GLWM_GENERATE;
-				this->landscape_source = USE_ORIGINAL;
-				Window::SetDirty();
+				SetPlane(GLAND_TERRAIN_SOURCE, &this->landscape_source, USE_ORIGINAL);
 				break;
 
 			case GLAND_TAB_SETTINGS_TO_MAP:
-				this->active_tab = SELPLANE_MAP;
-				Window::SetDirty();
+				SetPlane(GLAND_TAB, &this->active_tab, SELPLANE_MAP);
 				break;
 			case GLAND_TAB_MAP_TO_SETTINGS:
-				this->active_tab = SELPLANE_SETTINGS;
-				Window::SetDirty();
+				SetPlane(GLAND_TAB, &this->active_tab, SELPLANE_SETTINGS);
 				break;
 
 			case GLAND_TEMPERATE: