Fix virtual scrolling MenuList font family dropdowns shrinking when wider content is unmounted (#3987)

* Fix virtual scrolling MenuList dropdowns shrinking when wider content goes away

* Code review fixes

* Fix small CI workflow bug

* Stop scrolling in dropdowns from horizontally scrolling the control bar

* Use more robust way of getting commit hash in CI workflow

frontend/src/components/floating-menus/MenuList.svelte

@@ -47,6 +47,8 @@
 	let virtualScrollingEntriesStart = 0;
 	let keydownListenerAdded = false;
 	let destroyed = false;
+	let maxMenuWidth = 0;
+	let resizeObserver: ResizeObserver | undefined = undefined;
 	// eslint-disable-next-line svelte/prefer-svelte-reactivity -- `loadedFonts` reactivity is driven by `loadedFontsGeneration`, not the Set itself
 	let loadedFonts = new Set<string>();
 	let loadedFontsGeneration = 0;
@@ -77,6 +79,7 @@
 	});
 	onDestroy(() => {
 		removeEventListener("keydown", keydown);
+		resizeObserver?.disconnect();
 		// Set the destroyed status in the closure kept by the awaited `tick()` in `onMount` in case that delayed run occurs after the component is destroyed
 		destroyed = true;
 	});
@@ -144,6 +147,15 @@
 			keydownListenerAdded = false;
 		}
 
+		// For virtual scrolling menus, observe width changes so the menu only grows and never shrinks while open
+		if (open && virtualScrolling) {
+			startMenuWidthObserver();
+		} else if (resizeObserver) {
+			resizeObserver.disconnect();
+			resizeObserver = undefined;
+			maxMenuWidth = 0;
+		}
+
 		highlighted = activeEntry;
 		dispatch("open", open);
 
@@ -156,14 +168,38 @@
 		});
 	}
 
-	function watchEntriesHash(_entriesHash: bigint) {
+	function watchEntriesHash(_: bigint) {
 		reactiveEntries = entries;
 	}
 
 	function watchRemeasureWidth(_: MenuListEntry[][], __: boolean) {
+		// Skip re-measurement for virtual scrolling menus since ResizeObserver handles their width
+		if (virtualScrolling) return;
+
 		self?.measureAndEmitNaturalWidth();
 	}
 
+	async function startMenuWidthObserver() {
+		await tick();
+		// Guard against the menu having closed during the tick
+		if (!open) return;
+
+		const floatingMenuContentDiv = self?.div()?.querySelector("[data-floating-menu-content]");
+		if (!(floatingMenuContentDiv instanceof HTMLElement)) return;
+
+		maxMenuWidth = 0;
+
+		resizeObserver?.disconnect();
+		resizeObserver = new ResizeObserver(() => {
+			const width = floatingMenuContentDiv.scrollWidth;
+			if (width > maxMenuWidth) {
+				maxMenuWidth = width;
+				floatingMenuContentDiv.style.minWidth = `${maxMenuWidth}px`;
+			}
+		});
+		resizeObserver.observe(floatingMenuContentDiv);
+	}
+
 	function onScroll(e: Event) {
 		if (!virtualScrollingEntryHeight) return;
 		virtualScrollingEntriesStart = e.target instanceof HTMLElement ? e.target.scrollTop : 0;

frontend/src/components/layout/FloatingMenu.svelte

@@ -492,7 +492,7 @@
 		<div class="tail" bind:this={tail}></div>
 	{/if}
 	{#if displayContainer}
-		<div class="floating-menu-container" bind:this={floatingMenuContainer}>
+		<div class="floating-menu-container" bind:this={floatingMenuContainer} on:wheel|stopPropagation>
 			<LayoutCol class="floating-menu-content" styles={{ "min-width": minWidthStyleValue }} {scrollableY} bind:this={floatingMenuContent} data-floating-menu-content>
 				<slot />
 			</LayoutCol>

frontend/src/utility-functions/input.ts

@@ -225,7 +225,7 @@ export function onWheelScroll(e: WheelEvent, editor: EditorWrapper) {
 
 	// Redirect vertical scroll wheel movement into a horizontal scroll on a horizontally scrollable element
 	// There seems to be no possible way to properly employ the browser's smooth scrolling interpolation
-	const horizontalScrollableElement = e.target instanceof Element && e.target.closest("[data-scrollable-x]");
+	const horizontalScrollableElement = e.target instanceof Element && !e.target.closest("[data-scrollable-y]") && e.target.closest("[data-scrollable-x]");
 	if (horizontalScrollableElement && e.deltaY !== 0) {
 		horizontalScrollableElement.scrollTo(horizontalScrollableElement.scrollLeft + e.deltaY, 0);
 		return;