[Designer] Designer and schema don’t agree on casing of attribute values

[sabberworm]

Problem Description

Designer creates certain attributes with an upper-cased first letter, which then shows up in code view as not adhering to the JSON schema:

When the casing is corrected to match the schema, designer then no longer recognizes it:

Affected properties that I have seen so far: size, weight, color, horizontalAlignment, spacing. There might be others.

Card JSON

{
    "type": "AdaptiveCard",
    "body": [
        {
            "type": "TextBlock",
            "size": "Medium",
            "weight": "Bolder",
            "text": "${title}",
            "style": "heading",
            "wrap": true
        }
    ],
    "$schema": "http://adaptivecards.io/schemas/adaptive-card.json",
    "version": "1.6"
}