diff -r e706da6b8ddc src/newgrf_gui.cpp
--- a/src/newgrf_gui.cpp	Sat May 22 19:59:37 2010 +0000
+++ b/src/newgrf_gui.cpp	Sun May 23 10:30:12 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 +645,54 @@
 		}
 	}
 
+	virtual void OnDragDrop(Point pt, int widget)
+	{
+		if (widget == SNGRFS_FILE_LIST) {
+			if (this->active_sel != NULL) {
+				GRFConfig *from_config = this->active_sel;
+				GRFConfig *prev_from_config = NULL;
+				uint from_offset = 0;
+				for (GRFConfig *cursor = this->actives; cursor != NULL && cursor != from_config; prev_from_config = cursor, cursor = cursor->next, from_offset++) {}
+
+				NWidgetBase *nw = this->GetWidget<NWidgetBase>(SNGRFS_FILE_LIST);
+				uint to_offset = (pt.y - nw->pos_y) / nw->resize_y + this->vscroll.GetPosition();
+
+				if (from_offset != to_offset) { // Don't move NewGRF file over itself
+					GRFConfig *to_config = this->actives;
+					GRFConfig *prev_to_config = NULL;
+					for (uint i = 0; to_config != NULL && i < to_offset; prev_to_config = to_config, to_config = to_config->next, i++) {}
+
+					/* Detach NewGRF file of its original position. */
+					if (prev_from_config == NULL) { // Detach from start of list
+						this->actives = this->actives->next;
+					} else {
+						prev_from_config->next = from_config->next;
+					}
+
+					/* Attach NewGRF file to its new position. */
+					if (from_offset < to_offset) { // Move down NewGRF file
+						from_config->next = to_config->next;
+						to_config->next = from_config;
+					} else if (from_offset > to_offset) { //Move up NewGRF file
+						if (prev_to_config == NULL) { // Move at start of the list
+							this->actives = from_config;
+							from_config->next = to_config;
+						} else {
+							from_config->next = to_config;
+							prev_to_config->next = from_config;
+						}
+					}
+
+					this->vscroll.ScrollTowards(to_offset);
+					this->preset = -1;
+					this->InvalidateData();
+				}
+			}
+		}
+
+		ResetObjectToPlace();
+	}
+
 	virtual void OnDropdownSelect(int widget, int index)
 	{
 		if (index == -1) {