The thinnest line thickness is thinner than in Adobe and it is not scaled according to the scale factor.

Observed:

Observed when loading a document: 

When the WatermarkBehavior is set to either HideOnTextEntered or HideOnClick, moving the focus with the Tab key will not move it on the first press.

To work this around, handle the PreviewKeyDown event and manually move the focus to the next element when the Tab key is the e.Key property's value.

Cell contents are missing when the header size is assigned through the e.Size property of the HeaderSizeEventArgs in the HeaderSizeNeeded event handler of RadVirtualGrid.

This happens only for some of the cells and when the viewport has many rows and columns.

To work this around, instead of setting the header size in the HeaderSizeNeeded event handler, use the ColumnWidth property of RadVirtualGrid.

<telerik:RadVirtualGrid ColumnWidth="50" />

The items of the RadComboBox control flicker when scrolling and the Windows 11 theme is applied.

To work this around, a new Style with TargetType="RadComboBoxItem" could be created for the ItemContainerStyle property of RadComboBox. Then, set the BorderBrush and ThemeHelper.MouseOverBrush properties to "#F9F9F9".

xmlns:helpers="clr-namespace:Telerik.Windows.Controls.Theming.Helpers;assembly=Telerik.Windows.Controls"

<telerik:RadComboBox.ItemContainerStyle>
    <Style TargetType="telerik:RadComboBoxItem">
        <Setter Property="helpers:ThemeHelper.MouseOverBrush" Value="#F9F9F9" />
        <Setter Property="BorderBrush" Value="#F9F9F9"/>
    </Style>
</telerik:RadComboBox.ItemContainerStyle>

The DataContext of RadPane's content is lost when showing its preview in the DockingNavigator.

As a workaround, you could set the DataContext of the content element could be set explicitly.

Pixel bug in Lightweight Templates of RadGridView in VisualStudio2013 and Office2013 themes:

No horizontal grid lines when cell has background color:

Most likely bottom margin of PART_CellBorder not set in VisualStudio2013 Theme. In Office2016 PART_CellBorder.Margin="0 0 0 1"

Single line folding regions is falsely recognized (by default it should be avoided) and messes up with outer regions.
For example
1 [

2 [ inner region]

3]

There should be no folding button on the inner line.  Collapsing line 1 does not collapse 3 but only 1 and 2 which is wrong.