Fixes #37658

src/vs/editor/browser/controller/textAreaHandler.ts

@@ -542,7 +542,7 @@ export class TextAreaHandler extends ViewPart {
 		tac.setHeight(1);
 
 		if (this._context.configuration.editor.viewInfo.glyphMargin) {
-			tac.setClassName('monaco-editor-background textAreaCover ' + Margin.CLASS_NAME);
+			tac.setClassName('monaco-editor-background textAreaCover ' + Margin.OUTER_CLASS_NAME);
 		} else {
 			if (this._context.configuration.editor.viewInfo.renderLineNumbers !== RenderLineNumbersType.Off) {
 				tac.setClassName('monaco-editor-background textAreaCover ' + LineNumbersOverlay.CLASS_NAME);

src/vs/editor/browser/viewParts/margin/margin.ts

@@ -14,6 +14,7 @@ import * as viewEvents from 'vs/editor/common/view/viewEvents';
 export class Margin extends ViewPart {
 
 	public static readonly CLASS_NAME = 'glyph-margin';
+	public static readonly OUTER_CLASS_NAME = 'margin';
 
 	private _domNode: FastDomNode<HTMLElement>;
 	private _canUseLayerHinting: boolean;
@@ -42,7 +43,7 @@ export class Margin extends ViewPart {
 
 	private _createDomNode(): FastDomNode<HTMLElement> {
 		let domNode = createFastDomNode(document.createElement('div'));
-		domNode.setClassName('margin');
+		domNode.setClassName(Margin.OUTER_CLASS_NAME);
 		domNode.setPosition('absolute');
 		domNode.setAttribute('role', 'presentation');
 		domNode.setAttribute('aria-hidden', 'true');