diff --git a/src/openrct2/windows/mapgen.c b/src/openrct2/windows/mapgen.c
index a505cdd6f6..a03051bd47 100644
--- a/src/openrct2/windows/mapgen.c
+++ b/src/openrct2/windows/mapgen.c
@@ -1301,21 +1301,25 @@ static void window_mapgen_heightmap_paint(rct_window *w, rct_drawpixelinfo *dpi)
 
 	// Smooth strength label and value
 	const uint8 strengthColour = _heightmapSmoothMap ? enabledColour : disabledColour;
+	sint16 strength = _heightmapSmoothStrength;
 	gfx_draw_string_left(dpi, STR_MAPGEN_SMOOTH_STRENGTH, NULL, strengthColour, w->x + 5, w->y + w->widgets[WIDX_HEIGHTMAP_STRENGTH].top + 1);
-	gfx_draw_string_left(dpi, STR_COMMA16, &_heightmapSmoothStrength, strengthColour, w->x + w->widgets[WIDX_HEIGHTMAP_STRENGTH].left + 1, w->y + w->widgets[WIDX_HEIGHTMAP_STRENGTH].top + 1);
+	gfx_draw_string_left(dpi, STR_COMMA16, &strength, strengthColour, w->x + w->widgets[WIDX_HEIGHTMAP_STRENGTH].left + 1, w->y + w->widgets[WIDX_HEIGHTMAP_STRENGTH].top + 1);
 
 	// Low label and value
 	const uint8 labelColour = _heightmapLoaded ? enabledColour : disabledColour;
+	sint16 low = _heightmapLow;
 	gfx_draw_string_left(dpi, STR_MAPGEN_SIMPLEX_NOISE_LOW_, NULL, labelColour, w->x + 5, w->y + w->widgets[WIDX_HEIGHTMAP_LOW].top + 1);
-	gfx_draw_string_left(dpi, STR_COMMA16, &_heightmapLow, labelColour, w->x + w->widgets[WIDX_HEIGHTMAP_LOW].left + 1, w->y + w->widgets[WIDX_HEIGHTMAP_LOW].top + 1);
+	gfx_draw_string_left(dpi, STR_COMMA16, &low, labelColour, w->x + w->widgets[WIDX_HEIGHTMAP_LOW].left + 1, w->y + w->widgets[WIDX_HEIGHTMAP_LOW].top + 1);
 
 	// High label and value
+	sint16 high = _heightmapHigh;
 	gfx_draw_string_left(dpi, STR_MAPGEN_SIMPLEX_NOISE_HIGH, NULL, labelColour, w->x + 5, w->y + w->widgets[WIDX_HEIGHTMAP_HIGH].top + 1);
-	gfx_draw_string_left(dpi, STR_COMMA16, &_heightmapHigh, labelColour, w->x + w->widgets[WIDX_HEIGHTMAP_HIGH].left + 1, w->y + w->widgets[WIDX_HEIGHTMAP_HIGH].top + 1);
+	gfx_draw_string_left(dpi, STR_COMMA16, &high, labelColour, w->x + w->widgets[WIDX_HEIGHTMAP_HIGH].left + 1, w->y + w->widgets[WIDX_HEIGHTMAP_HIGH].top + 1);
 
 	// Water level label and value
+	sint16 waterLevel = _waterLevel;
 	gfx_draw_string_left(dpi, STR_WATER_LEVEL_LABEL, NULL, labelColour, w->x + 5, w->y + w->widgets[WIDX_HEIGHTMAP_WATER_LEVEL].top + 1);
-	gfx_draw_string_left(dpi, STR_COMMA16, &_waterLevel, labelColour, w->x + w->widgets[WIDX_HEIGHTMAP_WATER_LEVEL].left + 1, w->y + w->widgets[WIDX_HEIGHTMAP_WATER_LEVEL].top + 1);
+	gfx_draw_string_left(dpi, STR_COMMA16, &waterLevel, labelColour, w->x + w->widgets[WIDX_HEIGHTMAP_WATER_LEVEL].left + 1, w->y + w->widgets[WIDX_HEIGHTMAP_WATER_LEVEL].top + 1);
 }
 
 #pragma endregion