TinyMCE: Insert/Edit image dialog shows unsupported properties

Description

Prerequisite: The site must be configured for HTML5 (Default).

Steps to reproduce:

1. Place the cursor in a content area.
2. Select Insert/Edit image from the TinyMCE toolbar.
3. Browse and select an image under Image URL on the General tab.
4. Switch to the Appearance tab and note the available options.
5. Click Insert.
6. Select the inserted image and click Insert/Edit image again.
7. Switch to the Appearance tab and note the available options.

Actual result: The dialog box in step 4 displays more options than the dialog box in step 7.

Expected result: The dialog box in step 4 should look like the dialog box in step 7. The dialog box should only display options supported by HTML5 (on HTML5 sites).