[Google Chrome] Triple-clicking a heading and then pressing backspace forces the text below to inherit the deleted heading styles

[Keyser Soze]

We are using a MindTouch implementation of CKEditor.

Follow these steps to reproduce the issue:

1. Open the latest version of Google Chrome
2. Create a new page
3. Type three words into the header
4. Highlight the words and set them as H1
5. Type five words below your new header, making sure they are plain text
6. Triple click the middle word in the header to highlight the whole line
7. Press backspace
8. Notice the plaintext below has now inherited the H1 styling

This does not happen in IE9.

[Piotrek Koszuliński]

Triple click makes the following selection:

<h1>[foo</h1>
<p>]bar</p>

We use in this case the default algorithm which simply merges the 2nd block into the 1st one. This leaves:

<h1>bar</h1>

We could improve this algorithm though, to handle this situation differently. If the first block is partially selected, then it could be removed and the second block could be maintained. But this leads to other questions. E.g. what should happen if the second block is also fully selected? I can see e.g. that Firefox leaves no block at all after that... This is a totally incorrect result.

[Jakub Ś]

Please note that this is how Chrome handles it by default. If you try same thing in native contenteditable element you will get same result.