Fix broken chat variable highlights (microsoft#222322)

Author: roblourens

src/vs/workbench/contrib/chat/browser/contrib/chatDynamicVariables.ts

@@ -50,7 +50,7 @@ export class ChatDynamicVariableModel extends Disposable implements IChatWidgetC
 		this._register(widget.inputEditor.onDidChangeModelContent(e => {
 			e.changes.forEach(c => {
 				// Don't mutate entries in _variables, since they will be returned from the getter
-				const originalNumVariables = this._variables.length;
+				let didModifyState = false;
 				this._variables = coalesce(this._variables.map(ref => {
 					const intersection = Range.intersectRanges(ref.range, c.range);
 					if (intersection && !intersection.isEmpty()) {
@@ -63,9 +63,11 @@ export class ChatDynamicVariableModel extends Disposable implements IChatWidgetC
 								text: '',
 							}]);
 						}
+						didModifyState = true;
 						return null;
 					} else if (Range.compareRangesUsingStarts(ref.range, c.range) > 0) {
 						const delta = c.text.length - c.rangeLength;
+						didModifyState = true;
 						return {
 							...ref,
 							range: {
@@ -80,7 +82,7 @@ export class ChatDynamicVariableModel extends Disposable implements IChatWidgetC
 					return ref;
 				}));
 
-				if (this._variables.length !== originalNumVariables) {
+				if (didModifyState) {
 					this._onDidChangeInputState.fire();
 				}
 			});