diff --git a/packages/frontend/src/components/MkPostForm.vue b/packages/frontend/src/components/MkPostForm.vue
index 86557b12df..b3bcfcc137 100644
--- a/packages/frontend/src/components/MkPostForm.vue
+++ b/packages/frontend/src/components/MkPostForm.vue
@@ -5,7 +5,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 
 <template>
 <div
-	:class="[$style.root, { [$style.modal]: modal, _popup: modal }]"
+	:class="[$style.root]"
 	@dragover.stop="onDragover"
 	@dragenter="onDragenter"
 	@dragleave="onDragleave"
@@ -114,7 +114,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 </template>
 
 <script lang="ts" setup>
-import { inject, watch, nextTick, onMounted, defineAsyncComponent, provide, shallowRef, ref, computed, useTemplateRef, onUnmounted } from 'vue';
+import { watch, nextTick, onMounted, defineAsyncComponent, provide, shallowRef, ref, computed, useTemplateRef, onUnmounted } from 'vue';
 import * as mfm from 'mfm-js';
 import * as Misskey from 'misskey-js';
 import insertTextAtCursor from 'insert-text-at-cursor';
@@ -161,8 +161,6 @@ import { closeTip } from '@/tips.js';
 
 const $i = ensureSignin();
 
-const modal = inject(DI.inModal, false);
-
 const props = withDefaults(defineProps<PostFormProps & {
 	fixed?: boolean;
 	autofocus?: boolean;
@@ -1447,13 +1445,6 @@ defineExpose({
 .root {
 	position: relative;
 	container-type: inline-size;
-
-	&.modal {
-		width: 100%;
-		max-width: 520px;
-		overflow-x: clip;
-		overflow-y: auto;
-	}
 }
 
 //#region header
@@ -1722,7 +1713,8 @@ html[data-color-scheme=light] .preview {
 	min-width: 100%;
 	width: 100%;
 	min-height: 90px;
-	height: 100%;
+	max-height: 500px;
+	field-sizing: content;
 }
 
 .textCount {
diff --git a/packages/frontend/src/components/MkPostFormDialog.vue b/packages/frontend/src/components/MkPostFormDialog.vue
index ba8d3a7210..a7cf8a37cf 100644
--- a/packages/frontend/src/components/MkPostFormDialog.vue
+++ b/packages/frontend/src/components/MkPostFormDialog.vue
@@ -14,6 +14,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 	<MkPostForm
 		ref="form"
 		:class="$style.form"
+		class="_popup"
 		v-bind="props"
 		autofocus
 		freezeAfterPosted
@@ -73,7 +74,8 @@ function onModalClosed() {
 
 <style lang="scss" module>
 .form {
-	max-height: 100%;
+	width: 100%;
+	max-width: 520px;
 	margin: 0 auto auto auto;
 }
 </style>