compute position/width of output action bar.

Author: rebornix

src/vs/workbench/contrib/notebook/browser/media/notebook.css

@@ -263,10 +263,13 @@
 	position: absolute;
 	top: 4px;
 	left: -32px;
-	width: 16px;
 	height: 16px;
 	cursor: pointer;
-	padding: 6px;
+	padding: 6px 0px;
+}
+
+.monaco-workbench .notebookOverlay .output .cell-output-toolbar .actions-container {
+	justify-content: center;
 }
 
 .monaco-workbench .notebookOverlay .output pre {

src/vs/workbench/contrib/notebook/browser/notebookEditorWidget.ts

@@ -556,6 +556,7 @@ export class NotebookEditorWidget extends Disposable implements INotebookEditor
 			cellRunGutter,
 			cellBottomMargin,
 			codeCellLeftMargin,
+			markdownCellLeftMargin,
 			markdownCellBottomMargin,
 			markdownCellTopMargin,
 			bottomToolbarGap: bottomCellToolbarGap,
@@ -717,12 +718,17 @@ export class NotebookEditorWidget extends Disposable implements INotebookEditor
 		styleSheets.push(`.notebookOverlay .output { margin: 0px ${cellRightMargin}px 0px ${codeCellLeftMargin + cellRunGutter}px; }`);
 		styleSheets.push(`.notebookOverlay .output { width: calc(100% - ${codeCellLeftMargin + cellRunGutter + cellRightMargin}px); }`);
 
+		// output toolbar
+		styleSheets.push(`.monaco-workbench .notebookOverlay .output .cell-output-toolbar { left: -${cellRunGutter}px; }`);
+		styleSheets.push(`.monaco-workbench .notebookOverlay .output .cell-output-toolbar { width: ${cellRunGutter}px; }`);
+
 		styleSheets.push(`.notebookOverlay .output-show-more-container { margin: 0px ${cellRightMargin}px 0px ${codeCellLeftMargin + cellRunGutter}px; }`);
 		styleSheets.push(`.notebookOverlay .output-show-more-container { width: calc(100% - ${codeCellLeftMargin + cellRunGutter + cellRightMargin}px); }`);
-
-		styleSheets.push(`.notebookOverlay .cell-list-container > .monaco-list > .monaco-scrollable-element > .monaco-list-rows > .monaco-list-row div.cell.markdown { padding-left: ${cellRunGutter}px; }`);
 		styleSheets.push(`.notebookOverlay .cell .run-button-container { width: ${cellRunGutter}px; left: ${codeCellLeftMargin}px }`);
 		styleSheets.push(`.monaco-workbench .notebookOverlay > .cell-list-container > .monaco-list > .monaco-scrollable-element > .monaco-list-rows > .monaco-list-row .execution-count-label { left: ${codeCellLeftMargin}px; width: ${cellRunGutter}px; }`);
+
+		styleSheets.push(`.notebookOverlay .cell-list-container > .monaco-list > .monaco-scrollable-element > .monaco-list-rows > .monaco-list-row div.cell.markdown { padding-left: ${cellRunGutter}px; }`);
+		styleSheets.push(`.monaco-workbench .notebookOverlay > .cell-list-container .notebook-folding-indicator { left: ${(markdownCellLeftMargin - 20) / 2}px; }`);
 		styleSheets.push(`.notebookOverlay .monaco-list .monaco-list-row :not(.webview-backed-markdown-cell) .cell-focus-indicator-top { height: ${cellTopMargin}px; }`);
 		styleSheets.push(`.notebookOverlay .monaco-list .monaco-list-row .cell-focus-indicator-side { bottom: ${bottomCellToolbarGap}px; }`);
 		styleSheets.push(`.notebookOverlay .monaco-list .monaco-list-row.code-cell-row .cell-focus-indicator-left,