Slow performance with documents that contain many custom styles. 

Implement pasting of images similar to Excel. 

Investigate if the performance with large files can be improved. Currently a document with a million ros is opened slowly and the memory consumption is high. 

A filter cannot be applied to the RadSpreadsheet when a sheet is protected even though the Filter option in the protection dialog is checked. 

The data validation error message box has an invalid size when shown multiple times

Defined names do not appear in the Name Box.

DataValidation of a list with defined names is not taking the source into account. As a result, values are not displayed as options in the cell drop-down list.

InvalidOperationException (Sequence contains no matching element) when editing a note.

If the Spreadsheet ribbon has a custom template which hides the Style Gallery, when the Styles collection is edited, a NullReferenceException is thrown. This is because the change causes changes in the Style Gallery while the template of the Style Gallery is not yet applied.

In Excel, when you copy a range and then paste it into a larger one, the values are repeated to fill the larger range. This can be included in RadSpreadsheet as well.

Searching with Ctrl-F in a sheet with many rows takes a long time.

The sheet navigation does not work with specific theme and document.

telerik:Label's Context is set to itself and is throwing an error while searching for a not existing 'Title' property within itself.

Currently, Custom IconSets are not supported when having Conditional Formatting scenarios.

NullReferenceException when the document contains paragraph elements with no text. 

Fill down (Ctrl-D) is not working in a protected worksheet with an unlocked range of cells.

PrintPreviewControl throws NullReferenceException when it is in the GridView Print example. 

The cursor position is changed when one clicks in the middle of a formula. The cursor is moved to the end of the text. 

One cannot reference another sheet in a formula by using the UI 

When certain files are imported, an exception with message" is invalid column name" is thrown.