diff --git a/src/vs/editor/common/model.ts b/src/vs/editor/common/model.ts
index df8ad4833db..2bf83cca827 100644
--- a/src/vs/editor/common/model.ts
+++ b/src/vs/editor/common/model.ts
@@ -1077,7 +1077,7 @@ export interface ITextModel {
 	 * @param cursorStateComputer A callback that can compute the resulting cursors state after the edit operations have been executed.
 	 * @return The cursor state returned by the `cursorStateComputer`.
 	 */
-	pushEditOperations(beforeCursorState: Selection[], editOperations: IIdentifiedSingleEditOperation[], cursorStateComputer: ICursorStateComputer): Selection[] | null;
+	pushEditOperations(beforeCursorState: Selection[] | null, editOperations: IIdentifiedSingleEditOperation[], cursorStateComputer: ICursorStateComputer): Selection[] | null;
 
 	/**
 	 * Change the end of line sequence. This is the preferred way of
diff --git a/src/vs/editor/common/model/editStack.ts b/src/vs/editor/common/model/editStack.ts
index 92bab6cd80e..9b5d53c6bda 100644
--- a/src/vs/editor/common/model/editStack.ts
+++ b/src/vs/editor/common/model/editStack.ts
@@ -75,7 +75,7 @@ export class EditStackElement implements IUndoRedoElement {
 	}
 }
 
-export class MultiEditStackElement implements IUndoRedoElement {
+export class MultiModelEditStackElement implements IUndoRedoElement {
 
 	public readonly label: string;
 	private _isOpen: boolean;
@@ -185,7 +185,7 @@ export class EditStack {
 		editStackElement.append(this._model, [], getModelEOL(this._model), this._model.getAlternativeVersionId(), null);
 	}
 
-	public pushEditOperation(beforeCursorState: Selection[], editOperations: IIdentifiedSingleEditOperation[], cursorStateComputer: ICursorStateComputer | null): Selection[] | null {
+	public pushEditOperation(beforeCursorState: Selection[] | null, editOperations: IIdentifiedSingleEditOperation[], cursorStateComputer: ICursorStateComputer | null): Selection[] | null {
 		const editStackElement = this._getOrCreateEditStackElement(beforeCursorState);
 		const inverseEditOperations = this._model.applyEdits(editOperations);
 		const afterCursorState = EditStack._computeCursorState(cursorStateComputer, inverseEditOperations);
diff --git a/src/vs/editor/common/model/textModel.ts b/src/vs/editor/common/model/textModel.ts
index a535afe069f..bba23d05d11 100644
--- a/src/vs/editor/common/model/textModel.ts
+++ b/src/vs/editor/common/model/textModel.ts
@@ -1187,7 +1187,7 @@ export class TextModel extends Disposable implements model.ITextModel {
 		return result;
 	}
 
-	public pushEditOperations(beforeCursorState: Selection[], editOperations: model.IIdentifiedSingleEditOperation[], cursorStateComputer: model.ICursorStateComputer | null): Selection[] | null {
+	public pushEditOperations(beforeCursorState: Selection[] | null, editOperations: model.IIdentifiedSingleEditOperation[], cursorStateComputer: model.ICursorStateComputer | null): Selection[] | null {
 		try {
 			this._onDidChangeDecorations.beginDeferredEmit();
 			this._eventEmitter.beginDeferredEmit();
@@ -1198,7 +1198,7 @@ export class TextModel extends Disposable implements model.ITextModel {
 		}
 	}
 
-	private _pushEditOperations(beforeCursorState: Selection[], editOperations: model.ValidAnnotatedEditOperation[], cursorStateComputer: model.ICursorStateComputer | null): Selection[] | null {
+	private _pushEditOperations(beforeCursorState: Selection[] | null, editOperations: model.ValidAnnotatedEditOperation[], cursorStateComputer: model.ICursorStateComputer | null): Selection[] | null {
 		if (this._options.trimAutoWhitespace && this._trimAutoWhitespaceLines) {
 			// Go through each saved line number and insert a trim whitespace edit
 			// if it is safe to do so (no conflicts with other edits).
@@ -1213,22 +1213,24 @@ export class TextModel extends Disposable implements model.ITextModel {
 			// Sometimes, auto-formatters change ranges automatically which can cause undesired auto whitespace trimming near the cursor
 			// We'll use the following heuristic: if the edits occur near the cursor, then it's ok to trim auto whitespace
 			let editsAreNearCursors = true;
-			for (let i = 0, len = beforeCursorState.length; i < len; i++) {
-				let sel = beforeCursorState[i];
-				let foundEditNearSel = false;
-				for (let j = 0, lenJ = incomingEdits.length; j < lenJ; j++) {
-					let editRange = incomingEdits[j].range;
-					let selIsAbove = editRange.startLineNumber > sel.endLineNumber;
-					let selIsBelow = sel.startLineNumber > editRange.endLineNumber;
-					if (!selIsAbove && !selIsBelow) {
-						foundEditNearSel = true;
+			if (beforeCursorState) {
+				for (let i = 0, len = beforeCursorState.length; i < len; i++) {
+					let sel = beforeCursorState[i];
+					let foundEditNearSel = false;
+					for (let j = 0, lenJ = incomingEdits.length; j < lenJ; j++) {
+						let editRange = incomingEdits[j].range;
+						let selIsAbove = editRange.startLineNumber > sel.endLineNumber;
+						let selIsBelow = sel.startLineNumber > editRange.endLineNumber;
+						if (!selIsAbove && !selIsBelow) {
+							foundEditNearSel = true;
+							break;
+						}
+					}
+					if (!foundEditNearSel) {
+						editsAreNearCursors = false;
 						break;
 					}
 				}
-				if (!foundEditNearSel) {
-					editsAreNearCursors = false;
-					break;
-				}
 			}
 
 			if (editsAreNearCursors) {
diff --git a/src/vs/monaco.d.ts b/src/vs/monaco.d.ts
index 628fea221a7..9fb1bf00712 100644
--- a/src/vs/monaco.d.ts
+++ b/src/vs/monaco.d.ts
@@ -1884,7 +1884,7 @@ declare namespace monaco.editor {
 		 * @param cursorStateComputer A callback that can compute the resulting cursors state after the edit operations have been executed.
 		 * @return The cursor state returned by the `cursorStateComputer`.
 		 */
-		pushEditOperations(beforeCursorState: Selection[], editOperations: IIdentifiedSingleEditOperation[], cursorStateComputer: ICursorStateComputer): Selection[] | null;
+		pushEditOperations(beforeCursorState: Selection[] | null, editOperations: IIdentifiedSingleEditOperation[], cursorStateComputer: ICursorStateComputer): Selection[] | null;
 		/**
 		 * Change the end of line sequence. This is the preferred way of
 		 * changing the eol sequence. This will land on the undo stack.