Limit size of siblings list and some bug fixes

svelte/src/layout/ToggleButton.svelte

@@ -7,6 +7,7 @@ let {
 	group_middle = false,
 	group_last = false,
 	highlight = true,
+	flat = false,
 	action,
 	children,
 }: {
@@ -17,6 +18,7 @@ let {
 	group_middle?: boolean;
 	group_last?: boolean;
 	highlight?: boolean;
+	flat?: boolean;
 	action?: (e: MouseEvent) => void;
 	children?: import('svelte').Snippet;
 } = $props();
@@ -37,6 +39,7 @@ const click = (e: MouseEvent) => {
 	class:group_first
 	class:group_middle
 	class:group_last
+	class:flat
 >
 	{#if on}
 		<i class="icon">{icon_on}</i>