diff --git a/src/vs/vscode.proposed.d.ts b/src/vs/vscode.proposed.d.ts
index 7d8742f5c7667..d319e4c8d305b 100644
--- a/src/vs/vscode.proposed.d.ts
+++ b/src/vs/vscode.proposed.d.ts
@@ -1352,7 +1352,7 @@ declare module 'vscode' {
 	}
 
 	export interface NotebookEditorCellEdit {
-		insert(index: number, content: string, language: string, type: CellKind, outputs: CellOutput[], metadata: NotebookCellMetadata | undefined): void;
+		insert(index: number, content: string | string[], language: string, type: CellKind, outputs: CellOutput[], metadata: NotebookCellMetadata | undefined): void;
 		delete(index: number): void;
 	}
 
diff --git a/src/vs/workbench/api/common/extHostNotebook.ts b/src/vs/workbench/api/common/extHostNotebook.ts
index 0cf95ab387ca6..f65958ccebacb 100644
--- a/src/vs/workbench/api/common/extHostNotebook.ts
+++ b/src/vs/workbench/api/common/extHostNotebook.ts
@@ -402,11 +402,12 @@ export class NotebookEditorCellEdit {
 		}
 	}
 
-	insert(index: number, content: string, language: string, type: CellKind, outputs: vscode.CellOutput[], metadata: vscode.NotebookCellMetadata | undefined): void {
+	insert(index: number, content: string | string[], language: string, type: CellKind, outputs: vscode.CellOutput[], metadata: vscode.NotebookCellMetadata | undefined): void {
 		this._throwIfFinalized();
 
+		const sourceArr = Array.isArray(content) ? content : content.split(/\r|\n|\r\n/g);
 		let cell = {
-			source: [content],
+			source: sourceArr,
 			language,
 			cellKind: type,
 			outputs: (outputs as any[]), // TODO@rebornix
diff --git a/src/vs/workbench/contrib/notebook/browser/notebook.css b/src/vs/workbench/contrib/notebook/browser/notebook.css
index 1cc8fd26c983c..3dba77055f653 100644
--- a/src/vs/workbench/contrib/notebook/browser/notebook.css
+++ b/src/vs/workbench/contrib/notebook/browser/notebook.css
@@ -206,6 +206,7 @@
 	position: absolute;
 	display: flex;
 	opacity: 0;
+	transition: opacity 0.2s ease-in-out;
 }
 
 .monaco-workbench .part.editor > .content .notebook-editor > .cell-list-container > .monaco-list > .monaco-scrollable-element > .monaco-list-rows > .monaco-list-row .cell-bottom-toolbar-container:hover {