Plans: Fix adding plan lines in viewport map mode

src/plans_gui.cpp

@@ -107,7 +107,7 @@ struct PlansWindow : Window {
 				DoCommandP(0, _local_company, 0, CMD_ADD_PLAN, CcAddPlan);
 				break;
 			case WID_PLN_ADD_LINES:
-				if (_current_plan) HandlePlacePushButton(this, widget, SPR_CURSOR_MOUSE, HT_POINT);
+				if (_current_plan) HandlePlacePushButton(this, widget, SPR_CURSOR_MOUSE, HT_POINT | HT_MAP);
 				break;
 			case WID_PLN_DELETE:
 				if (this->selected != INT_MAX) {
@@ -416,7 +416,7 @@ void CcAddPlan(const CommandCost &result, TileIndex tile, uint32 p1, uint32 p2,
 		((PlansWindow *) w)->SelectPlan(_current_plan->index);
 		if (!w->IsWidgetLowered(WID_PLN_ADD_LINES)) {
 			w->SetWidgetDisabledState(WID_PLN_ADD_LINES, false);
-			HandlePlacePushButton(w, WID_PLN_ADD_LINES, SPR_CURSOR_MOUSE, HT_POINT);
+			HandlePlacePushButton(w, WID_PLN_ADD_LINES, SPR_CURSOR_MOUSE, HT_POINT | HT_MAP);
 		}
 	}
 }

src/tilehighlight_type.h

@@ -30,6 +30,7 @@ enum HighLightStyle {
 	HT_NEW_POLY  = 0xC00, ///< start completly new polyline; implies #HT_POLY
 	HT_DRAG_MASK = 0x0F8, ///< Mask for the tile drag-type modes.
 	HT_TUNNEL    = 0x1000,///< tunnel highlight hint
+	HT_MAP       = 0x2000,///< Allow in viewport map mode
 
 	/* lower bits (used with HT_LINE and HT_RAIL):
 	 * (see ASCII art in table/autorail.h for a visual interpretation) */

src/viewport.cpp

@@ -4060,7 +4060,7 @@ bool HandleViewportDoubleClicked(Window *w, int x, int y)
 bool HandleViewportClicked(const Viewport *vp, int x, int y, bool double_click)
 {
 	/* No click in smallmap mode except for plan making. */
-	if (vp->zoom >= ZOOM_LVL_DRAW_MAP && !(_thd.place_mode == HT_POINT && _thd.select_proc == DDSP_DRAW_PLANLINE)) return true;
+	if (vp->zoom >= ZOOM_LVL_DRAW_MAP && !(_thd.place_mode & HT_MAP)) return true;
 
 	const Vehicle *v = CheckClickOnVehicle(vp, x, y);
 
@@ -4086,6 +4086,8 @@ bool HandleViewportClicked(const Viewport *vp, int x, int y, bool double_click)
 		return true;
 	}
 
+	if (vp->zoom >= ZOOM_LVL_DRAW_MAP) return true;
+
 	if (CheckClickOnViewportSign(vp, x, y)) return true;
 	bool result = CheckClickOnLandscape(vp, x, y);