Cutting the widget scrolls editor to the end (with t/468)

[f1ames]

Are you reporting a feature request or a bug?

Bug

Provide detailed reproduction steps (if any)

1. Go to http://tests.ckeditor.test:1030/tests/plugins/clipboard/manual/draganddrop
2. Select the widget from the first editor.
3. Press CTRL + X.

Expected result

Editor scrolls to the end.

Actual result

Editor does not scroll at all or scroll position is restored.

Other details

• Browser: Edge 16+
• OS: Windows
• CKEditor version: major with Support for Clipboard API in Edge #468
• Installed CKEditor plugins: clipboard

[f1ames]

Looks like the breaking commit is the first one: 5571884. Not sure why ATM.

[f1ames]

The exact line is https://github.com/ckeditor/ckeditor-dev/blob/2bcbf1ffd39e4bb897c9c1b1930337214da83136/plugins/clipboard/plugin.js#L526

while the previous flow doesn't executed this code (due to CKEDITOR.plugins.clipboard.isCustomCopyCutSupported) the issue was not visible.

---

When this line is skipped, on widget cut editor content does not jump (which happens on major) so this is a little different case.

[f1ames]

This issue is caused by the fact that when copying/cutting widgets, pastebin is still used. Widgets copySingleWidget function:

https://github.com/ckeditor/ckeditor-dev/blob/2bcbf1ffd39e4bb897c9c1b1930337214da83136/plugins/widget/plugin.js#L3083-L3169

is called on copy/cut here:
https://github.com/ckeditor/ckeditor-dev/blob/2bcbf1ffd39e4bb897c9c1b1930337214da83136/plugins/widget/plugin.js#L3503-L3520

or here:
https://github.com/ckeditor/ckeditor-dev/blob/2bcbf1ffd39e4bb897c9c1b1930337214da83136/plugins/widget/plugin.js#L2690-L2704

Initially I thought scrolling is caused by container holding real selection, but the cause here is pastebin container.

The quick workaround for the issue is to fix pastebin container type from:

copybinName = ( editor.blockless || CKEDITOR.env.ie ) ? 'span' : 'div'

to:

copybinName = ( editor.blockless || ( CKEDITOR.env.ie && CKEDITOR.env.version < 16 ) ) ? 'span' : 'div'

which brings the same behaviour as on the major branch (the editor jumps - scrolling back to where caret is after widget removal).

---

Is pastebin really needed here?

The clipboard plugin uses pastebin only for browsers not supporting Clipboard API (IE browsers), but for widgets it is used always. I think we should consider restricting its usage only from browsers which really needs it, especially that:

1. copySingleWidget is called first and it utilizes CKEDITOR.editable.getHtmlFromRange to prepare HTML which is copied by the browser to a clipboard/dataTransfer.
2. clipboard plugin listeners are executed, which for browsers supporting Clipboard API, creates CKEDITOR.plugins.clipboard.dataTransfer.
3. CKEDITOR.plugins.clipboard.dataTransfer object upon creation inserts text/html data to clipboard (using CKEDITOR.editor.getSelectedHtml) overwriting html which was inserted via pastebin.

Also CKEDITOR.editable.getHtmlFromRange is the base of the CKEDITOR.editor.getSelectedHtml method so the output should is the same.

[f1ames]

Extracted #1169.

[Comandeer]

Closed in #1170.