diff --git a/flow-libs/atom.js.flow b/flow-libs/atom.js.flow
index c9ca8232..175e8856 100644
--- a/flow-libs/atom.js.flow
+++ b/flow-libs/atom.js.flow
@@ -240,6 +240,7 @@ declare class atom$DisplayMarkerLayer {
   destroy(): void,
   clear(): void,
   isDestroyed(): boolean,
+  markBufferPosition(position: atom$PointLike, options?: MarkerOptions): atom$Marker,
   markBufferRange(range: atom$Range | atom$RangeLike, options: MarkerOptions): atom$Marker,
   getMarkers(): Array<atom$Marker>,
 }
@@ -773,7 +774,7 @@ declare class atom$TextEditor extends atom$Model {
   // Event Subscription
   onDidChange(callback: () => void): IDisposable,
   onDidChangePath(callback: (newPath: string) => mixed): IDisposable,
-  onDidStopChanging(callback: () => void): IDisposable,
+  onDidStopChanging(callback: () => mixed): IDisposable,
   onDidChangeCursorPosition(callback: (event: ChangeCursorPositionEvent) => mixed):
     IDisposable,
   onDidDestroy(callback: () => mixed): IDisposable,
@@ -818,6 +819,7 @@ declare class atom$TextEditor extends atom$Model {
   getText(): string,
   getTextInBufferRange(range: atom$RangeLike): string,
   getLineCount(): number,
+  getLastScreenRow(): number,
 
   // Mutating Text
   setText(text: string, options?: InsertTextOptions): void,
@@ -874,6 +876,7 @@ declare class atom$TextEditor extends atom$Model {
   getDecorations(options?: {class?: string, type?: string}): Array<atom$Decoration>,
 
   // Markers
+  addMarkerLayer(): atom$DisplayMarkerLayer,
   getDefaultMarkerLayer(): atom$DisplayMarkerLayer,
   markBufferPosition(position: atom$PointLike, options?: MarkerOptions): atom$Marker,
   markBufferRange(range: atom$RangeLike, options?: MarkerOptions): atom$Marker,
diff --git a/modules/atom-ide-ui/pkg/atom-ide-global/lib/backports/installTextEditorStyles.js b/modules/atom-ide-ui/pkg/atom-ide-global/lib/backports/installTextEditorStyles.js
index d1dbc4b8..81100d41 100644
--- a/modules/atom-ide-ui/pkg/atom-ide-global/lib/backports/installTextEditorStyles.js
+++ b/modules/atom-ide-ui/pkg/atom-ide-global/lib/backports/installTextEditorStyles.js
@@ -16,6 +16,8 @@ import {Observable} from 'rxjs';
 import invariant from 'assert';
 import semver from 'semver';
 
+const DEFAULT_FONT_STACK = "Menlo, Consolas, 'DejaVu Sans Mono', monospace";
+
 export default function installTextEditorStyles(): IDisposable {
   if (semver.gte(atom.appVersion, '1.26.0')) {
     // this behavior is part of 1.26 and greater
@@ -46,7 +48,7 @@ export default function installTextEditorStyles(): IDisposable {
       const styleSheetSource = `
         atom-workspace {
           --editor-font-size: ${fontSize}px;
-          --editor-font-family: ${fontFamily};
+          --editor-font-family: ${fontFamily || DEFAULT_FONT_STACK};
           --editor-line-height: ${lineHeight};
         }
       `;