Currently <big> and <small> tags are not supported and the text inside is not imported.

Currently HtmlFormatProvider does not export/import tables with alignment (left, center, right).

It seems that the characters of Arabic words are reversed on export. Moreover, Arabic letters has different letter forms according to their position in the word (contextual letter forms) - beginning, end, middle, isolated. It seems that same character should be exported to PDF with different charcode depending on the character positioning. 

The invalid values should be skipped and the document should be successfully imported.

Check all possible shorthand properties, e.g. border-[left/top/right/bottom]. Also check CSS properties like border-[left/top/right/bottom]-[color/style/width].

Add support for inset borders for tables and table cells (Inset Line Border in OOXML).

Nested tables inherit alignment from its parent table or table cell when importing a document from HTML, but they shouldn't.
The paragraphs are also aligned incorrectly when their parent table has its align attribute set.

Currently ignored words are marked only in-memory using internal properties of the document model. Make them persist, similar to what MS Word do.

Note: In the DOCX format, the document is marked as "clear" (doesn't contain spell check errors) and all misspelled words are enclosed with an errProof annotation.

The word is temporary marked as correct and when another word is added to the dictionary, the ignored one is highlighted again. As a workaround could be used the Ignore All option.

When adding a comment it should be marked as created from the current user. Layer with tool tips should be added to show this information. Also comment balloons should contain it.

Improve the performance when multiple paragraphs are selected and deleted.

When trying to import a document containing bookmark and BookmarkRangeEnd is after the last paragraph, a StackOverflowException is thrown in IntervalNode while trying to rebuild the document cache. (RadDocumentChildrenCache.RebuildTree()).

The same could be observed if the bookmark end is last in the header/footer, between table cells in the RadDocument body, or when all paragraphs after the bookmark range end are hidden (with vanish property).

Workaround: Detect the problematic annotations and remove them:
foreach (var rangeStart in document.EnumerateChildrenOfType<AnnotationRangeStart>())
{
    if (rangeStart.End == null || rangeStart.End.Parent == null || rangeStart.End.Parent.Parent == null)
    {
        //MessageBox.Show("This indicates a problem.");
        rangeStart.Parent.Children.Remove(rangeStart);
    }
}

Note: Until 2017 R2 SP1 release StackOverflowException is thrown, after this release an ArgumentException should be thrown.

When the specified length of the stream is larger than the actual one, Adobe throws errors and removes the image.

Workaround:

Set the format provider settings:

PdfFormatProvider provider = new PdfFormatProvider();
PdfExportSettings exportSettings = new PdfExportSettings();
exportSettings.ContentsDeflaterCompressionLevel = 9;
exportSettings.ImagesDeflaterCompressionLevel = 9;
provider.ExportSettings = exportSettings;

When the paragraph formatting symbol has a formatting, different than the one of the spans in this paragraph, the bullet is not aligned to the baseline of the text

When a list associated with list style is copied from a document (source document), and is pasted in another document (target document), and the target document contains list style with the same name, the the list style from source is added to the target, which creates two list styles with the same name in the target document.

In the same scenario, MS Word uses the list style from the target, and do not add the list style from the source.

When a list is copied from one document (source) to another document (target) and the target contains custom list with different name, the paste command does not paste the list in the target.

Steps to reproduce:
1. Open two instances of RadRichTexbox
2. In the first RRTB create new list style -> List1 and use it to create a list
3. In the second RRTB create a new list style -> List 2 and use it to create a list
4. Copy the list from the second RRTB and try to paste it after the list in the first RRTB

Expected: The list is pasted.
Actual: The list is not pasted, but the list style is added to the List Library.

When a color property has default (auto) value, do not export a tag which points to omitted defintion in the color table. For example, if a span has transparent highlight (the default one), do not export the \highlight tag since this might lead to some incorrect rendering of the document from other readers - WordPad for example.

Currently, when an option is chosen from the drop-downs in Page Layout -> Page Setup -> Size/Margin/Orientation/Columns, the command is executed, but the item corresponding to the current value is not selected. For example, if the caret is in a Section with A3 size, Size -> drop-down -> A3 should be selected.

The ChangeListStyleCommand has an event named ListStyleChangedChanged  which is never raised.