diff --git a/app/forms/disk-create.tsx b/app/forms/disk-create.tsx
index ded6cec33..8cb8418f3 100644
--- a/app/forms/disk-create.tsx
+++ b/app/forms/disk-create.tsx
@@ -20,10 +20,10 @@ import {
   type Image,
 } from '@oxide/api'
 
+import { ComboboxField } from '~/components/form/fields/ComboboxField'
 import { DescriptionField } from '~/components/form/fields/DescriptionField'
 import { DiskSizeField } from '~/components/form/fields/DiskSizeField'
 import { toImageComboboxItem } from '~/components/form/fields/ImageSelectField'
-import { ListboxField } from '~/components/form/fields/ListboxField'
 import { NameField } from '~/components/form/fields/NameField'
 import { RadioField } from '~/components/form/fields/RadioField'
 import { SideModalForm } from '~/components/form/SideModalForm'
@@ -171,6 +171,7 @@ const DiskSourceField = ({
     field: { value, onChange },
   } = useController({ control, name: 'diskSource' })
   const diskSizeField = useController({ control, name: 'size' }).field
+  const diskImageIdField = useController({ control, name: 'diskSource.imageId' }).field
 
   return (
     <>
@@ -210,7 +211,7 @@ const DiskSourceField = ({
           />
         )}
         {value.type === 'image' && (
-          <ListboxField
+          <ComboboxField
             control={control}
             name="diskSource.imageId"
             label="Source image"
@@ -218,6 +219,9 @@ const DiskSourceField = ({
             isLoading={areImagesLoading}
             items={images.map((i) => toImageComboboxItem(i, true))}
             required
+            onInputChange={() => {
+              diskImageIdField.onChange()
+            }}
             onChange={(id) => {
               const image = images.find((i) => i.id === id)! // if it's selected, it must be present
               const imageSizeGiB = image.size / GiB
@@ -252,9 +256,13 @@ const SnapshotSelectField = ({ control }: { control: Control<DiskCreate> }) => {
 
   const snapshots = snapshotsQuery.data?.items || []
   const diskSizeField = useController({ control, name: 'size' }).field
+  const diskSnapshotIdField = useController({
+    control,
+    name: 'diskSource.snapshotId',
+  }).field
 
   return (
-    <ListboxField
+    <ComboboxField
       control={control}
       name="diskSource.snapshotId"
       label="Source snapshot"
@@ -278,6 +286,9 @@ const SnapshotSelectField = ({ control }: { control: Control<DiskCreate> }) => {
       })}
       isLoading={snapshotsQuery.isPending}
       required
+      onInputChange={() => {
+        diskSnapshotIdField.onChange()
+      }}
       onChange={(id) => {
         const snapshot = snapshots.find((i) => i.id === id)! // if it's selected, it must be present
         const snapshotSizeGiB = snapshot.size / GiB
diff --git a/test/e2e/disks.e2e.ts b/test/e2e/disks.e2e.ts
index 13482ad3e..eb4a573f2 100644
--- a/test/e2e/disks.e2e.ts
+++ b/test/e2e/disks.e2e.ts
@@ -80,20 +80,20 @@ test.describe('Disk create', () => {
 
   test('from snapshot', async ({ page }) => {
     await page.getByRole('radio', { name: 'Snapshot' }).click()
-    await page.getByRole('button', { name: 'Source snapshot' }).click()
+    await page.getByRole('combobox', { name: 'Source snapshot' }).click()
     await page.getByRole('option', { name: 'delete-500' }).click()
   })
 
   // max-size snapshot required a fix
   test('from max-size snapshot', async ({ page }) => {
     await page.getByRole('radio', { name: 'Snapshot' }).click()
-    await page.getByRole('button', { name: 'Source snapshot' }).click()
+    await page.getByRole('combobox', { name: 'Source snapshot' }).click()
     await page.getByRole('option', { name: 'snapshot-max' }).click()
   })
 
   test('from image', async ({ page }) => {
     await page.getByRole('radio', { name: 'Image' }).click()
-    await page.getByRole('button', { name: 'Source image' }).click()
+    await page.getByRole('combobox', { name: 'Source image' }).click()
     await page.getByRole('option', { name: 'image-3' }).click()
   })
 
diff --git a/test/e2e/instance-disks.e2e.ts b/test/e2e/instance-disks.e2e.ts
index f6c59b063..a8569f4ec 100644
--- a/test/e2e/instance-disks.e2e.ts
+++ b/test/e2e/instance-disks.e2e.ts
@@ -117,7 +117,7 @@ test('Create disk', async ({ page }) => {
   await expect(createForm.getByRole('textbox', { name: 'Description' })).toBeVisible()
 
   await page.getByRole('radio', { name: 'Snapshot' }).click()
-  await page.getByRole('button', { name: 'Source snapshot' }).click()
+  await page.getByRole('combobox', { name: 'Source snapshot' }).click()
   await page.getByRole('option', { name: 'snapshot-heavy' }).click()
 
   await createForm.getByRole('button', { name: 'Create disk' }).click()