From b2592583c47a121f8f0401175e050b962c9589ff Mon Sep 17 00:00:00 2001
From: Bruno Windels <brunow@matrix.org>
Date: Fri, 24 May 2019 18:54:29 +0200
Subject: [PATCH 1/3] maintain caret at current line when position is on
 newline part

---
 src/editor/caret.js | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/src/editor/caret.js b/src/editor/caret.js
index 974c8802a4..5ff9dbc950 100644
--- a/src/editor/caret.js
+++ b/src/editor/caret.js
@@ -20,13 +20,23 @@ export function setCaretPosition(editor, model, caretPosition) {
     sel.removeAllRanges();
     const range = document.createRange();
     const {parts} = model;
+    const {index} = caretPosition;
+    let {offset} = caretPosition;
     let lineIndex = 0;
     let nodeIndex = -1;
-    for (let i = 0; i <= caretPosition.index; ++i) {
+    for (let i = 0; i <= index; ++i) {
         const part = parts[i];
         if (part && part.type === "newline") {
-            lineIndex += 1;
-            nodeIndex = -1;
+            if (i < index) {
+                lineIndex += 1;
+                nodeIndex = -1;
+            } else {
+                // if index points at a newline part,
+                // put the caret at the end of the previous part
+                // so it stays on the same line
+                const prevPart = parts[i - 1];
+                offset = prevPart ? prevPart.text.length : 0;
+            }
         } else {
             nodeIndex += 1;
         }
@@ -34,7 +44,7 @@ export function setCaretPosition(editor, model, caretPosition) {
     let focusNode;
     const lineNode = editor.childNodes[lineIndex];
     if (lineNode) {
-        if (lineNode.childNodes.length === 0 && caretPosition.offset === 0) {
+        if (lineNode.childNodes.length === 0 && offset === 0) {
             focusNode = lineNode;
         } else {
             focusNode = lineNode.childNodes[nodeIndex];
@@ -50,7 +60,7 @@ export function setCaretPosition(editor, model, caretPosition) {
         range.collapse(false);
     } else {
         // make sure we have a text node
-        range.setStart(focusNode, caretPosition.offset);
+        range.setStart(focusNode, offset);
         range.collapse(true);
     }
     sel.addRange(range);

From 4fc23022f435e193793f56c09abe46e6bd4814d9 Mon Sep 17 00:00:00 2001
From: Bruno Windels <brunow@matrix.org>
Date: Tue, 28 May 2019 10:01:16 +0200
Subject: [PATCH 2/3] remove all non-first-br nodes on new empty line, not just
 first one

nextSibling returned null after calling removeNode,
so get the nextSibling first
---
 src/editor/render.js | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/editor/render.js b/src/editor/render.js
index caea18e3ca..58ef0eaee1 100644
--- a/src/editor/render.js
+++ b/src/editor/render.js
@@ -61,12 +61,13 @@ export function renderModel(editor, model) {
             let foundBR = false;
             let partNode = lineContainer.firstChild;
             while (partNode) {
+                const nextNode = partNode.nextSibling;
                 if (!foundBR && partNode.tagName === "BR") {
                     foundBR = true;
                 } else {
                     lineContainer.removeChild(partNode);
                 }
-                partNode = partNode.nextSibling;
+                partNode = nextNode;
             }
             if (!foundBR) {
                 lineContainer.appendChild(document.createElement("br"));

From 6b680ff6811bec3a01670c3c1f14f102ffed3b62 Mon Sep 17 00:00:00 2001
From: Bruno Windels <brunow@matrix.org>
Date: Tue, 28 May 2019 10:34:29 +0200
Subject: [PATCH 3/3] fallback to setting caret on line node for empty lines

instead of setting at the end of the editor
---
 src/editor/caret.js | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/src/editor/caret.js b/src/editor/caret.js
index 5ff9dbc950..f93e9604d5 100644
--- a/src/editor/caret.js
+++ b/src/editor/caret.js
@@ -44,14 +44,11 @@ export function setCaretPosition(editor, model, caretPosition) {
     let focusNode;
     const lineNode = editor.childNodes[lineIndex];
     if (lineNode) {
-        if (lineNode.childNodes.length === 0 && offset === 0) {
+        focusNode = lineNode.childNodes[nodeIndex];
+        if (!focusNode) {
             focusNode = lineNode;
-        } else {
-            focusNode = lineNode.childNodes[nodeIndex];
-
-            if (focusNode && focusNode.nodeType === Node.ELEMENT_NODE) {
-                focusNode = focusNode.childNodes[0];
-            }
+        } else if (focusNode.nodeType === Node.ELEMENT_NODE) {
+            focusNode = focusNode.childNodes[0];
         }
     }
     // node not found, set caret at end