diff --git a/web/chat/chat-input-text-area.react.js b/web/chat/chat-input-text-area.react.js
--- a/web/chat/chat-input-text-area.react.js
+++ b/web/chat/chat-input-text-area.react.js
@@ -11,11 +11,19 @@
   +focus: boolean,
   +currentText: string,
   +setCurrentText: (text: string) => void,
+  +onChangePosition: () => void,
 };
 
 const ChatInputTextArea: React.ComponentType<Props> = React.memo<Props>(
   function ChatInputTextArea(props: Props) {
-    const { currentText, focus, escape, send, setCurrentText } = props;
+    const {
+      currentText,
+      focus,
+      escape,
+      send,
+      setCurrentText,
+      onChangePosition,
+    } = props;
     const textareaRef = React.useRef(null);
 
     const focusAndUpdateText = React.useCallback(() => {
@@ -48,7 +56,8 @@
         const newHeight = Math.min(textarea.scrollHeight, 150);
         textarea.style.height = `${newHeight}px`;
       }
-    }, []);
+      onChangePosition();
+    }, [onChangePosition]);
 
     React.useEffect(() => {
       updateHeight();
diff --git a/web/chat/edit-message-provider.js b/web/chat/edit-message-provider.js
--- a/web/chat/edit-message-provider.js
+++ b/web/chat/edit-message-provider.js
@@ -7,11 +7,19 @@
 import type { ChatMessageInfoItem } from 'lib/selectors/chat-selectors.js';
 import type { ThreadInfo } from 'lib/types/thread-types';
 
+export type ModalPosition = {
+  +left: number,
+  +top: number,
+  +width: number,
+  +height: number,
+};
+
 export type EditState = {
   +messageInfo: ChatMessageInfoItem,
   +threadInfo: ThreadInfo,
   +editedMessageDraft: ?string,
   +isError: boolean,
+  +position?: ModalPosition,
 };
 
 type EditModalContextType = {
@@ -20,6 +28,7 @@
   +editState: ?EditState,
   +setDraft: string => void,
   +setError: boolean => void,
+  +updatePosition: ModalPosition => void,
 };
 
 const EditModalContext: React.Context<EditModalContextType> =
@@ -29,6 +38,7 @@
     editState: null,
     setDraft: () => {},
     setError: () => {},
+    updatePosition: () => {},
   });
 
 type Props = {
@@ -75,6 +85,18 @@
     },
     [editState, setEditState],
   );
+
+  const updatePosition = React.useCallback(
+    (position: ModalPosition) => {
+      invariant(editState, 'editState should be set in updatePosition');
+      setEditState({
+        ...editState,
+        position,
+      });
+    },
+    [editState, setEditState],
+  );
+
   const value = React.useMemo(
     () => ({
       renderEditModal,
@@ -82,8 +104,16 @@
       editState,
       setDraft,
       setError,
+      updatePosition,
     }),
-    [renderEditModal, clearEditModal, editState, setDraft, setError],
+    [
+      renderEditModal,
+      clearEditModal,
+      editState,
+      setDraft,
+      setError,
+      updatePosition,
+    ],
   );
 
   const modalOverlay = React.useMemo(() => {
diff --git a/web/chat/edit-text-message.react.js b/web/chat/edit-text-message.react.js
--- a/web/chat/edit-text-message.react.js
+++ b/web/chat/edit-text-message.react.js
@@ -2,6 +2,7 @@
 
 import classNames from 'classnames';
 import * as React from 'react';
+import { useCallback } from 'react';
 import { XCircle as XCircleIcon } from 'react-feather';
 
 import type { ChatMessageInfoItem } from 'lib/selectors/chat-selectors.js';
@@ -29,10 +30,12 @@
 
 function EditTextMessage(props: Props): React.Node {
   const { background, threadInfo, item } = props;
-  const { editState, clearEditModal, setDraft, setError } =
+  const { editState, clearEditModal, setDraft, setError, updatePosition } =
     useEditModalContext();
   const editMessage = useEditMessage();
 
+  const myRef = React.useRef(null);
+
   const editedMessageDraft = editState?.editedMessageDraft ?? '';
   const threadColor = threadInfo.color;
   const saveButtonColor: ButtonColor = React.useMemo(
@@ -71,6 +74,34 @@
     }
   };
 
+  const updateDimensions = useCallback(() => {
+    if (!myRef.current || !background) {
+      return;
+    }
+    const { left, top, width, height } = myRef.current.getBoundingClientRect();
+    updatePosition({
+      left,
+      top,
+      width,
+      height,
+    });
+  }, [background, updatePosition]);
+
+  React.useEffect(() => {
+    if (!background) {
+      return undefined;
+    }
+    window.addEventListener('resize', updateDimensions);
+    return () => {
+      window.removeEventListener('resize', updateDimensions);
+    };
+  }, [background, updateDimensions]);
+
+  React.useEffect(() => {
+    updateDimensions();
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, []);
+
   let editFailed;
   if (editState?.isError) {
     editFailed = (
@@ -87,12 +118,13 @@
   });
 
   return (
-    <div className={containerStyle}>
+    <div className={containerStyle} ref={myRef}>
       <div className={cssInputBar.inputBarTextInput}>
         <ChatInputTextArea
           focus={!background}
           currentText={editedMessageDraft}
           setCurrentText={setDraft}
+          onChangePosition={updateDimensions}
           send={checkAndEdit}
         />
       </div>