With the latest 21.2, if you attempt to drag a vertical window divider with a mouse, xemacs aborts due to an assert in `x-bevel-area' checking that `shadow-thickness > 0'. It would appear that `x-bevel-area' determines the `relief' of the object to be drawn by the `style' argument, rather than a positive or negative value for `shadow-thickness'. This being the case, `shadow-thickness' should be set to its absolute value after setting a `style' value, but before calling `x-bevel-area'. The following does it for me: 1999-09-11 Mike McEwan <mike(a)lotusland.demon.co.uk&gt; * redisplay-x.c (x_output_vertical_divider): reset `shadow_thickness' to absolute value after setting style. Prevents an abort in `x-bevel-area'. --- src/redisplay-x.c.orig Sun Sep 5 18:10:51 1999 +++ src/redisplay-x.c Sat Sep 11 18:00:00 1999 ＠＠ -1342,6 +1342,7 ＠＠ if (shadow_thickness < 0) { style = EDGE_BEVEL_IN; + shadow_thickness = abs(shadow_thickness); } else { -- Mike.