Fixes microsoft/monaco-editor#812

src/vs/editor/contrib/hover/hoverWidgets.ts

@@ -19,7 +19,7 @@ export class ContentHoverWidget extends Widget implements IContentWidget {
 	protected _editor: ICodeEditor;
 	private _isVisible: boolean;
 	private readonly _containerDomNode: HTMLElement;
-	private readonly _domNode: HTMLElement;
+	protected readonly _domNode: HTMLElement;
 	protected _showAtPosition: Position | null;
 	protected _showAtRange: Range | null;
 	private _stoleFocus: boolean;

src/vs/editor/contrib/hover/modesContentHover.ts

@@ -13,7 +13,7 @@ import { ICodeEditor } from 'vs/editor/browser/editorBrowser';
 import { Position } from 'vs/editor/common/core/position';
 import { IRange, Range } from 'vs/editor/common/core/range';
 import { ModelDecorationOptions } from 'vs/editor/common/model/textModel';
-import { DocumentColorProvider, Hover as MarkdownHover, HoverProviderRegistry, IColor } from 'vs/editor/common/modes';
+import { DocumentColorProvider, Hover as MarkdownHover, HoverProviderRegistry, IColor, TokenizationRegistry } from 'vs/editor/common/modes';
 import { getColorPresentations } from 'vs/editor/contrib/colorPicker/color';
 import { ColorDetector } from 'vs/editor/contrib/colorPicker/colorDetector';
 import { ColorPickerModel } from 'vs/editor/contrib/colorPicker/colorPickerModel';
@@ -238,6 +238,12 @@ export class ModesContentHoverWidget extends ContentHoverWidget {
 		this._register(editor.onDidChangeConfiguration((e) => {
 			this._hoverOperation.setHoverTime(this._editor.getOption(EditorOption.hover).delay);
 		}));
+		this._register(TokenizationRegistry.onDidChange((e) => {
+			if (this.isVisible && this._lastRange && this._messages.length > 0) {
+				this._domNode.textContent = '';
+				this._renderMessages(this._lastRange, this._messages);
+			}
+		}));
 	}
 
 	dispose(): void {