Color button throws an error when activated on a content containing HTML comments

[jswiderski]

Type of report

Bug

Provide detailed reproduction steps (if any)

1. Open https://codepen.io/mlewand/pen/eLpPvJ
2. Open the console.
3. Focus the editor.
4. Select all the contents (ctrl/cmd+a).
5. Click "Background Color" button in the toolbar.

Expected result

Panel gets opened.

Actual result

Panel gets opened but JS Error gets thrown as well.
Message: element.getComputedStyle is not a function
URI: /ckeditor/plugins/colorbutton/plugin.js
Line: 176
Code: currentColor = normalizeColor( element.getComputedStyle( type == 'back' ? 'background-color' : 'color' ) );

Other details

• Browser: Edge, Chrome, Firefox (seems to work fine in IE11)
• OS: Win10
• CKEditor version: 4.10.0
• Installed CKEditor plugins: There is a link to build.

NOTE: Problem doesn't occur if we add Paste From Word (PFW) plugin to the build. While having PFW may seem mandatory when pasting content from MS applications, I don't think JS error should be thrown.

[mlewand]

The reason why is this happening is that Outlook leaves some comments in the pasted markup, and colorbutton plugin breaks when iterating over comments. This clearly should not break the plugin.

As such it is not colorbutton bug, not related really to the Outlook. I'll update the issue appropriately.

It didn't happen with PFW plugin as it cleared the HTlML comments.

[mlewand]

The issue has been merged into upcoming 4.10.1 release. I have created a codepen fork that hotlinks nightly preview of upcoming minor release, you can find it here: https://codepen.io/mlewand/pen/ZMWaYW