diff --git a/kitty/cell_vertex.glsl b/kitty/cell_vertex.glsl
index 325d8d453..a9e5729b8 100644
--- a/kitty/cell_vertex.glsl
+++ b/kitty/cell_vertex.glsl
@@ -162,7 +162,8 @@ void main() {
     float cell_has_cursor = is_cursor(c, r);
     float is_block_cursor = step(float(cursor_fg_sprite_idx), 0.5);
     float cell_has_block_cursor = cell_has_cursor * is_block_cursor;
-    vec3 bg = color_to_vec(resolve_color(colors[bg_index], default_colors[bg_index]));
+    uint bg_as_uint = resolve_color(colors[bg_index], default_colors[bg_index]);
+    vec3 bg = color_to_vec(bg_as_uint);
     // }}}
 
     // Foreground {{{
@@ -200,7 +201,7 @@ void main() {
 
     // Background {{{
 #ifdef NEEDS_BACKROUND
-    float cell_has_non_default_bg = step(ONE, colors[bg_index] & BYTE_MASK);
+    float cell_has_non_default_bg = step(ONE, abs(bg_as_uint - default_colors[bg_index]));
 
 #if defined(BACKGROUND)
     background = bg;