Fixes theme background colors.

visualization-bundle/src/visualizers/monaco-text-diff-visualizer/MonacoEditor.tsx

@@ -109,7 +109,7 @@ export class MonacoEditor extends React.Component<{
 
 	render() {
 		return (
-			<div className="component-monaco-editor">
+			<div className="component-monaco-editor-diff-visualizer">
 				<div className="part-editor" ref={this.setEditorDiv} />
 			</div>
 		);

visualization-bundle/src/visualizers/monaco-text-diff-visualizer/style.scss

@@ -1,4 +1,13 @@
-.component-monaco-editor {
+.themeable {
+	--visualizer-monaco-editor-diff-visualizer-background: var(
+		--visualizer-background
+	);
+}
+
+.component-monaco-editor-diff-visualizer {
+	background-color: var(
+		--visualizer-monaco-editor-diff-visualizer-background
+	);
 	width: 100%;
 	height: 100%;
 	min-width: 0;