Merge branch 'master' into jgrpp

# Conflicts:
#	CMakeLists.txt
#	bin/ai/CMakeLists.txt
#	bin/game/CMakeLists.txt
#	src/ai/ai_info.cpp
#	src/company_base.h
#	src/economy.cpp
#	src/game/game_info.cpp
#	src/gfx_type.h
#	src/linkgraph/linkgraph_gui.cpp
#	src/palette.cpp
#	src/palette_func.h
#	src/saveload/saveload.h
#	src/saveload/vehicle_sl.cpp
#	src/ship_cmd.cpp
#	src/train_cmd.cpp
#	src/vehicle_base.h
#	src/window.cpp
#	src/window_func.h

src/tracerestrict_gui.cpp

@@ -3797,7 +3797,7 @@ private:
 		/* Highlight the group if a vehicle is dragged over it */
 		if (slot_id == this->slot_over) {
 			GfxFillRect(left + WidgetDimensions::scaled.framerect.left, y + WidgetDimensions::scaled.framerect.top, right - WidgetDimensions::scaled.framerect.right,
-					y + this->tiny_step_height - WidgetDimensions::scaled.framerect.bottom - WidgetDimensions::scaled.matrix.top, _colour_gradient[COLOUR_GREY][7]);
+					y + this->tiny_step_height - WidgetDimensions::scaled.framerect.bottom - WidgetDimensions::scaled.matrix.top, GetColourGradient(COLOUR_GREY, SHADE_LIGHTEST));
 		}
 
 		/* draw the selected group in white, else we draw it in black */