diff --git a/src/group_gui.cpp b/src/group_gui.cpp
--- a/src/group_gui.cpp
+++ b/src/group_gui.cpp
@@ -262,7 +262,7 @@ private:
 	{
 		/* Highlight the group if a vehicle is dragged over it */
 		if (g_id == this->group_over) {
-			GfxFillRect(left + WidgetDimensions::scaled.bevel.left, y + WidgetDimensions::scaled.framerect.top, right - WidgetDimensions::scaled.bevel.right, y + this->tiny_step_height - 1 - WidgetDimensions::scaled.framerect.bottom, _colour_gradient[COLOUR_GREY][7]);
+			GfxFillRect(left + WidgetDimensions::scaled.bevel.left, y + WidgetDimensions::scaled.framerect.top, right - WidgetDimensions::scaled.bevel.right, y + this->tiny_step_height - 1 - WidgetDimensions::scaled.framerect.bottom, GetColourGradient(COLOUR_GREY, 7));
 		}
 
 		if (g_id == NEW_GROUP) return;
@@ -630,7 +630,7 @@ public:
 					for (size_t i = this->vscroll->GetPosition(); i < max; ++i) {
 						const Vehicle *v = this->vehgroups[i].GetSingleVehicle();
 						if (v->group_id != this->vli.index) {
-							GfxFillRect(mr.Shrink(WidgetDimensions::scaled.bevel), _colour_gradient[COLOUR_GREY][3], FILLRECT_CHECKER);
+							GfxFillRect(mr.Shrink(WidgetDimensions::scaled.bevel), GetColourGradient(COLOUR_GREY, 3), FILLRECT_CHECKER);
 						}
 						mr = mr.Translate(0, this->resize.step_height);
 					}