diff -r 17ad53748c7b -r eb8f1b5b2883 src/window.cpp
--- a/src/window.cpp	Fri Oct 19 22:46:55 2007 +0000
+++ b/src/window.cpp	Sat Oct 20 00:09:39 2007 +0000
@@ -1466,6 +1466,13 @@
 
 	w = FindWindowFromPt(_cursor.pos.x, _cursor.pos.y);
 
+	if (WP(w, vp_d).follow_vehicle != INVALID_VEHICLE && w == FindWindowById(WC_MAIN_WINDOW, 0)) {
+		/* If the main window is following a vehicle, then first let go of it! */
+		const Vehicle *veh = GetVehicle(WP(w, vp_d).follow_vehicle);
+		ScrollMainWindowTo(veh->x_pos, veh->y_pos, true); /* This also resets follow_vehicle */
+		return true;
+	}
+
 	if (!(_right_button_down || scrollwheel_scrolling) || w == NULL) {
 		_cursor.fix_at = false;
 		_scrolling_viewport = false;