[Designer] The 'Add a Column' button does not work in the Adaptive Card Designer

adamread85-afk

### Problem Description Creating a card layout in the online designer (https://adaptivecards.microsoft.com/designer.html) adding a column set shows a button which previously allowed users to "Add a Column". Clicking this button in Chrome or Edge does not work, making it impossible to design a column layout in the online designer without manually editing the json. ### Card JSON ```JSON { "type": "AdaptiveCard", "$schema": "https://adaptivecards.io/schemas/adaptive-card.json", "version": "1.6", "body": [ { "type": "TextBlock", "text": "Example card", "wrap": true }, { "type": "ColumnSet" } ] } ``` ### Screenshot <img width="1909" height="818" alt="Image" src="https://github.com/user-attachments/assets/2c868d9f-289d-47e4-8559-1a34816d0a88" />

RayHuang99

same issue when adding buttons, tried with different network/browser, issue persist. Please help to resolve it ASAP, cause the issue existing more than two months.