[AD] GUI kills OS cursor

[Chris <chris.kcat@xxxxxxxxxx>]

While playing around with my double-buffered dialogs (used 
gui_set_screen to set a memory buffer, then used a custom proc to blit 
it to the screen), I added the use of the OS cursor for smoother 
movement by calling show_os_cursor. However, I noticed that once I quit 
the first dialog and went into another one, I'd be back to use the 
software cursor.

I looked through gui.c and mouse.c, but I'm honestly not sure what the 
problem is. do_dialog checks if the mouse is being shown on the GUI 
bitmap (in my program, it is not), and if not, it sets the mouse to the 
GUI bitmap. Then, after the dialog quits, it sets the mouse back to the 
previous bitmap.

Now, my theory is that setting the OS cursor sets _mouse_screen to NULL, 
and the subsequent call to show_mouse(gui_bmp) is ignored (you still get 
the OS cursor). However, after the dialog exits, it calls 
show_mouse(mouse_screen), and if _mouse_screen was NULL, it'll 
effectively and ungratiously kill the OS cursor when it tries to 
"restore" the mouse to the previous bitmap.

If that happens to be the case, the attached patch should fix the 
problem. If that's not the case, or if there's an unforeseen side-effect 
of this change, then I'm not sure what to do...
Index: src/gui.c
===================================================================
RCS file: /cvsroot/alleg/allegro/src/gui.c,v
retrieving revision 1.73
diff -u -r1.73 gui.c
--- src/gui.c	31 Mar 2005 22:31:19 -0000	1.73
+++ src/gui.c	4 Apr 2005 21:45:42 -0000
@@ -792,7 +792,7 @@
          rest(1);
    }
 
-   if (_gfx_mode_set_count == screen_count)
+   if (_gfx_mode_set_count == screen_count && !(gfx_capabilities&GFX_HW_CURSOR))
       show_mouse(mouse_screen);
 
    return shutdown_dialog(player);