Re Microsoft/vscode-pull-request-github#652. Reply/Add comment button should...

Re Microsoft/vscode-pull-request-github#652. Reply/Add comment button should be enabled if the comment editor is not empty.

src/vs/workbench/parts/comments/electron-browser/commentThreadWidget.ts

@@ -334,7 +334,7 @@ export class ReviewZoneWidget extends ZoneWidget {
 		attachButtonStyler(button, this.themeService);
 		button.label = 'Add comment';
 
-		button.enabled = false;
+		button.enabled = model.getValueLength() > 0;
 		this._localToDispose.push(this._commentEditor.onDidChangeModelContent(_ => {
 			if (this._commentEditor.getValue()) {
 				button.enabled = true;