diff --git a/frontend/src/lib/components/LogViewer.svelte b/frontend/src/lib/components/LogViewer.svelte
index 2098e47a70..dbb8015459 100644
--- a/frontend/src/lib/components/LogViewer.svelte
+++ b/frontend/src/lib/components/LogViewer.svelte
@@ -367,7 +367,9 @@
 			>
 				{#if isLoading}
 					<div class="flex gap-2 items-center">
-						<Loader2 class="animate-spin" />
+						<!-- Same size as the Timer icon this swaps out for: an unsized (24px) spinner makes
+						     this header taller than the settled state and shoves the logs down while queued -->
+						<Loader2 size={small ? 10 : 12} class="animate-spin" />
 						{#if tag}
 							<div class="flex flex-row items-center gap-1">
 								<div class="text-secondary text-2xs">{tagLabel ?? 'tag'}: {tag}</div>
diff --git a/frontend/src/lib/components/ScriptEditor.svelte b/frontend/src/lib/components/ScriptEditor.svelte
index 936d49f3ee..13f3de2a7a 100644
--- a/frontend/src/lib/components/ScriptEditor.svelte
+++ b/frontend/src/lib/components/ScriptEditor.svelte
@@ -2270,14 +2270,10 @@
 							</div>
 						{:else}
 							{#key previewLayout}
-								<Splitpanes
-									horizontal={previewLayout !== 'bottom'}
-									class="!max-h-[calc(100%-{debugMode && isDebuggableScript
-										? '83'
-										: previewLayout === 'bottom'
-											? '0'
-											: '43'}px)]"
-								>
+								<!-- min-h-0 lets this shrink to the space the header row leaves it. Without it the
+								     100% height wins, the panes settle one header too tall, and any reflow during a
+								     run snaps them up and back. -->
+								<Splitpanes horizontal={previewLayout !== 'bottom'} class="min-h-0">
 									<Pane size={previewLayout === 'bottom' ? 40 : 33}>
 										{#if previewLayout === 'bottom' && !(debugMode && isDebuggableScript)}
 											<div class="px-3 pt-2 pb-1 flex items-center gap-2">
diff --git a/frontend/src/lib/components/home/TutorialBanner.svelte b/frontend/src/lib/components/home/TutorialBanner.svelte
index 9661d6738a..14d8b750c1 100644
--- a/frontend/src/lib/components/home/TutorialBanner.svelte
+++ b/frontend/src/lib/components/home/TutorialBanner.svelte
@@ -15,8 +15,20 @@
 	import { hasRoleAccess } from '$lib/tutorials/roleUtils'
 	import { onMount } from 'svelte'
 
-	let isDismissed = $state(false)
-	let hasCompletedAny = $state(false)
+	type BannerState = 'hidden' | 'start' | 'new'
+
+	// Deciding what to show needs an API round-trip, so the banner paints the state the last visit
+	// resolved to and reconciles once the sync answers. Guessing wrong once in a while beats
+	// reflowing the home page on every load; nothing cached means hidden, the direction that does
+	// not push the page down.
+	const TUTORIAL_BANNER_STATE_KEY = 'tutorial_banner_state'
+
+	const cachedState =
+		getLocalSetting(TUTORIAL_BANNER_DISMISSED_KEY) === 'true'
+			? 'hidden'
+			: getLocalSetting(TUTORIAL_BANNER_STATE_KEY)
+	let isDismissed = $state(cachedState !== 'start' && cachedState !== 'new')
+	let hasCompletedAny = $state(cachedState === 'new')
 
 	/**
 	 * Get all tutorial indexes that are accessible to the current user based on their role.
@@ -42,60 +54,81 @@
 		return indexes
 	})
 
+	function resolveState(state: BannerState) {
+		isDismissed = state === 'hidden'
+		hasCompletedAny = state === 'new'
+		// Last: persisting is best-effort, and a storage failure must not leave the banner stuck on
+		// whatever the cache said
+		storeLocalSetting(TUTORIAL_BANNER_STATE_KEY, state)
+	}
+
+	// The banner is interactive while the initial sync is still in flight, so a dismiss or a skip
+	// can land mid-await. Once that happens the user's choice wins and the sync must not resurrect
+	// the banner.
+	let userHidBanner = false
+
+	function hideBannerForUser() {
+		userHidBanner = true
+		resolveState('hidden')
+	}
+
 	onMount(async () => {
+		// Manually dismissed via the X button (soft dismiss, per-device). Checked before the network
+		// call so a dismissed banner can never flash back in.
+		if (getLocalSetting(TUTORIAL_BANNER_DISMISSED_KEY) === 'true') {
+			resolveState('hidden')
+			return
+		}
+
 		try {
 			// Sync tutorial progress from backend first
 			await syncTutorialsTodos()
-
-			// Check if banner has been manually dismissed via X button (soft dismiss, per-device)
-			const manuallyDismissed = getLocalSetting(TUTORIAL_BANNER_DISMISSED_KEY) === 'true'
-			if (manuallyDismissed) {
-				isDismissed = true
-				return
-			}
-
-			// Check if user deliberately skipped all tutorials (permanent dismiss, from backend)
-			if ($skippedAll) {
-				isDismissed = true
-				return
-			}
-
-			// Safe to check tutorialsToDo here since we awaited syncTutorialsTodos() above
-			// Filter tutorialsToDo to only include tutorials accessible to the user's role
-			const remainingAccessibleTutorials = $tutorialsToDo.filter((index) =>
-				accessibleTutorialIndexes.has(index)
-			)
-
-			// Calculate if user has completed at least one tutorial (for banner wording)
-			// This determines whether to show "New tutorial available!" or "Learn with interactive tutorials"
-			hasCompletedAny = remainingAccessibleTutorials.length < accessibleTutorialIndexes.size
-
-			// Hide banner if all accessible tutorials are completed (but can reappear with new tutorials)
-			if (remainingAccessibleTutorials.length === 0) {
-				isDismissed = true
-				return
-			}
-
-			// Show banner - user has accessible tutorials to complete
-			isDismissed = false
 		} catch (error) {
 			console.error('Failed to sync tutorial progress:', error)
-			// Fallback to manual dismissal check only if API call fails
-			isDismissed = getLocalSetting(TUTORIAL_BANNER_DISMISSED_KEY) === 'true'
+			// Keep whatever the last successful sync resolved to rather than guessing again
+			return
 		}
+
+		if (userHidBanner) {
+			return
+		}
+
+		// Check if user deliberately skipped all tutorials (permanent dismiss, from backend)
+		if ($skippedAll) {
+			resolveState('hidden')
+			return
+		}
+
+		// Safe to check tutorialsToDo here since we awaited syncTutorialsTodos() above
+		// Filter tutorialsToDo to only include tutorials accessible to the user's role
+		const remainingAccessibleTutorials = $tutorialsToDo.filter((index) =>
+			accessibleTutorialIndexes.has(index)
+		)
+
+		// Hide banner if all accessible tutorials are completed (but can reappear with new tutorials)
+		if (remainingAccessibleTutorials.length === 0) {
+			resolveState('hidden')
+			return
+		}
+
+		// Having completed at least one accessible tutorial switches the wording to
+		// "New tutorial available!" instead of "Learn with interactive tutorials"
+		resolveState(
+			remainingAccessibleTutorials.length < accessibleTutorialIndexes.size ? 'new' : 'start'
+		)
 	})
 
 	async function handleSkipAllTutorials() {
 		// Skip all tutorials and set skipped_all flag in backend (permanent)
 		await skipAllTodos()
 		await syncTutorialsTodos()
-		// No need to set localStorage - backend skipped_all flag is the source of truth
-		isDismissed = true
+		// No need to set the dismissed flag - backend skipped_all flag is the source of truth
+		hideBannerForUser()
 	}
 
 	function dismissBanner() {
 		storeLocalSetting(TUTORIAL_BANNER_DISMISSED_KEY, 'true')
-		isDismissed = true
+		hideBannerForUser()
 
 		const actions: ToastAction[] = [
 			{
diff --git a/frontend/src/lib/components/scriptEditor/LogPanel.svelte b/frontend/src/lib/components/scriptEditor/LogPanel.svelte
index 008a987999..f253beadc7 100644
--- a/frontend/src/lib/components/scriptEditor/LogPanel.svelte
+++ b/frontend/src/lib/components/scriptEditor/LogPanel.svelte
@@ -223,9 +223,11 @@
 										</div>
 									{:else}
 										<div class="text-sm text-primary p-2 flex justify-between items-center">
-											<span>
+											<!-- min-h pins this to the text-sm line box, and tracks it across root font
+											     sizes, so swapping the text for the spinner does not resize the row -->
+											<span class="flex items-center min-h-5">
 												{#if previewIsLoading}
-													<Loader2 class="animate-spin" />
+													<Loader2 size={14} class="animate-spin" />
 												{:else}
 													Test to see the result here
 												{/if}