diff --git a/degesch.c b/degesch.c
index 14f6476..5bdb58d 100644
--- a/degesch.c
+++ b/degesch.c
@@ -1288,14 +1288,15 @@ server_destroy (void *self)
 
 struct app_context
 {
+	bool no_colors;                     ///< Disable attribute printing
 	char *attrs_defaults[ATTR_COUNT];   ///< Default terminal attributes
 
 	// Configuration:
 
 	struct config config;               ///< Program configuration
 	char *attrs[ATTR_COUNT];            ///< Terminal attributes
-	bool no_colors;                     ///< Colour output mode
 	bool isolate_buffers;               ///< Isolate global/server buffers
+	bool beep_on_highlight;             ///< Beep on highlight
 
 	struct str_map servers;             ///< Our servers
 
@@ -1416,9 +1417,19 @@ static bool irc_is_this_us (struct server *s, const char *prefix);
 
 // --- Configuration -----------------------------------------------------------
 
-// TODO: "on_change" callbacks for everything
 static void on_config_attribute_change (struct config_item_ *item);
 
+#define TRIVIAL_BOOLEAN_ON_CHANGE(name)                                        \
+	static void                                                                \
+	on_config_ ## name ## _change (struct config_item_ *item)                  \
+	{                                                                          \
+		struct app_context *ctx = item->user_data;                             \
+		ctx->name = item->value.boolean;                                       \
+	}
+
+TRIVIAL_BOOLEAN_ON_CHANGE (isolate_buffers)
+TRIVIAL_BOOLEAN_ON_CHANGE (beep_on_highlight)
+
 static bool
 config_validate_nonjunk_string
 	(const struct config_item_ *item, struct error **e)
@@ -1557,11 +1568,13 @@ static struct config_schema g_config_behaviour[] =
 	{ .name      = "isolate_buffers",
 	  .comment   = "Don't leak messages from the server and global buffers",
 	  .type      = CONFIG_ITEM_BOOLEAN,
-	  .default_  = "off" },
+	  .default_  = "off",
+	  .on_change = on_config_isolate_buffers_change },
 	{ .name      = "beep_on_highlight",
 	  .comment   = "Beep when highlighted or on a new invisible PM",
 	  .type      = CONFIG_ITEM_BOOLEAN,
-	  .default_  = "on" },
+	  .default_  = "on",
+	  .on_change = on_config_beep_on_highlight_change },
 	{ .name      = "logging",
 	  .comment   = "Log buffer contents to file",
 	  .type      = CONFIG_ITEM_BOOLEAN,
@@ -2593,7 +2606,7 @@ log_formatter (struct app_context *ctx,
 	if (buffer->log_file)
 		buffer_line_write_to_log (ctx, line, buffer->log_file);
 
-	if (get_config_boolean (ctx->config.root, "behaviour.beep_on_highlight"))
+	if (ctx->beep_on_highlight)
 		if ((flags & BUFFER_LINE_HIGHLIGHT)
 		 || (buffer->type == BUFFER_PM && buffer != ctx->current_buffer))
 			input_ding (&ctx->input);
@@ -8748,10 +8761,6 @@ main (int argc, char *argv[])
 	init_poller_events (&ctx);
 	load_configuration (&ctx);
 
-	// TODO: this won't be needed after adding an "on_change" callback
-	ctx.isolate_buffers =
-		get_config_boolean (ctx.config.root, "behaviour.isolate_buffers");
-
 	// At this moment we can safely call any "on_change" callbacks
 	config_schema_call_changed (ctx.config.root);