diff -r a3cfaeee08f4 src/newgrf_gui.cpp
--- a/src/newgrf_gui.cpp	Sun May 23 22:14:22 2010 +0000
+++ b/src/newgrf_gui.cpp	Mon May 24 09:23:02 2010 +0200
@@ -22,6 +22,7 @@
 #include "sortlist_type.h"
 #include "querystring_gui.h"
 #include "core/geometry_func.hpp"
+#include "tilehighlight_func.h"
 
 #include "table/strings.h"
 #include "table/sprites.h"
@@ -482,6 +483,8 @@
 			}
 
 			case SNGRFS_FILE_LIST: { // Select an active GRF.
+				ResetObjectToPlace();
+
 				NWidgetBase *nw = this->GetWidget<NWidgetBase>(SNGRFS_FILE_LIST);
 				uint i = (pt.y - nw->pos_y) / nw->resize_y + this->vscroll.GetPosition();
 
@@ -494,7 +497,13 @@
 				this->avail_pos = -1;
 
 				this->InvalidateData();
-				if (click_count == 1) break;
+				if (click_count == 1) {
+					if (this->active_sel != NULL) {
+						/* Activate drag and drop */
+						SetObjectToPlaceWnd(SPR_CURSOR_MOUSE, PAL_NONE, HT_DRAG, this);
+					}
+					break;
+				}
 			}
 			/* Fall through with double click. */
 			case SNGRFS_REMOVE: { // Remove GRF
@@ -636,6 +645,58 @@
 		}
 	}
 
+	virtual void OnDragDrop(Point pt, int widget)
+	{
+		if (widget == SNGRFS_FILE_LIST && this->active_sel != NULL) {
+			GRFConfig *from = this->active_sel;
+			/* Gets the selected file offset in the active list and its predecessor. */
+			GRFConfig *from_prev = NULL;
+			uint from_pos = 0;
+			for (GRFConfig *cursor = this->actives; cursor != NULL; cursor = cursor->next) {
+				if (cursor == from) break;
+
+				from_prev = cursor;
+				from_pos++;
+			}
+
+			/* Gets the drag-and-drop destination offset. */
+			NWidgetBase *nw = this->GetWidget<NWidgetBase>(SNGRFS_FILE_LIST);
+			uint to_pos = (pt.y - nw->pos_y) / nw->resize_y + this->vscroll.GetPosition();
+
+			if (from_pos != to_pos) { // Don't move NewGRF file over itself
+				/* Gets destination file and its predecessor. */
+				GRFConfig *to = this->actives;
+				GRFConfig *to_prev = NULL;
+				for (uint i = 0; to != NULL && i < to_pos; to_prev = to, to = to->next, i++) {}
+
+				/* Detach NewGRF file of its original position. */
+				if (from_prev == NULL) { // Detach from start of list
+					this->actives = this->actives->next;
+				} else {
+					from_prev->next = from->next;
+				}
+
+				/* Attach NewGRF file to its new position. */
+				if (from_pos < to_pos) { // Move down NewGRF file
+					from->next = to->next;
+					to->next = from;
+				} else if (to_prev == NULL) { // Move up at start of the list
+					this->actives = from;
+					from->next = to;
+				} else { // Move up inside list
+					from->next = to;
+					to_prev->next = from;
+				}
+
+				this->vscroll.ScrollTowards(to_pos);
+				this->preset = -1;
+				this->InvalidateData();
+			}
+		}
+
+		ResetObjectToPlace();
+	}
+
 	virtual void OnDropdownSelect(int widget, int index)
 	{
 		if (index == -1) {