When there are split panes in a workbook, the topLeftCell property can be omitted. In this case, the format provider throws NullReferenceException.

With the current implementation, references like in the following expression cannot be evaluated and are treated as strings:
=SUM('C:\Users\Your user name\Desktop\[Workbook_1.xlsx]Sheet1'!A1:B2)

Comparison operators (equal '=', not equal '<>') doesn't work as expected with references to empty cells. For example, expressions of type '=IF(A1="", TRUE, FALSE)' are evaluated to false when A1 cell is empty. 

In MS Excel, such expression is evaluated to TRUE if the cell is empty - i.e. empty cell value is considered equal to an empty string "".

Workaround: Use ISBLANK function if possible. Its results are consistent with MS Excel.

For instance, when exporting FLOOR.MATH function a #NAME error is displayed initially.

Workaround: Select the cell in Excel, click in the formula bar and press Enter without changing anything. This fixes the #NAME error and Excel manages to successfully display the function result.

The MATCH function searches for a specified item in a range of cells and returns the relative position of the item found in this range.

A list of the supported functions is available at http://docs.telerik.com/devtools/document-processing/libraries/radspreadprocessing/features/formulas/functions

This function can be implemented as a custom function. Check the following resources for more details on how to achieve that:

- http://docs.telerik.com/devtools/document-processing/libraries/radspreadprocessing/features/formulas/custom-functions
- https://github.com/telerik/xaml-sdk/tree/master/Spreadsheet/CustomFunctions

Available in R3 2017 Official Release Version

When the default number formats for Accounting and Currency are used and the current culture is Russian, the number format is not parsed correctly.

Add support for TEXT function. The TEXT function allows changing the way a number appears by applying formatting to it using format codes.

TEXT(value, format_text)

A list of the supported functions is available at http://docs.telerik.com/devtools/document-processing/libraries/radspreadprocessing/features/formulas/functions 

This function can be implemented as a custom function. Check the following resources for more details on how to achieve that:

- http://docs.telerik.com/devtools/document-processing/libraries/radspreadprocessing/features/formulas/custom-functions 
- https://github.com/telerik/xaml-sdk/tree/master/Spreadsheet/WPF/CustomFunctions 

Add support for CHOOSE function. CHOOSE uses the number parameter to return a value from the list of value arguments. 

A list of the supported functions is available at http://docs.telerik.com/devtools/document-processing/libraries/radspreadprocessing/features/formulas/functions

This function can be implemented as a custom function. Check the following resources for more details on how to achieve that:

- http://docs.telerik.com/devtools/document-processing/libraries/radspreadprocessing/features/formulas/custom-functions
- https://github.com/telerik/xaml-sdk/tree/master/Spreadsheet/CustomFunctions

Available in R2 2017 Official Release.

Provide the customers with the ability to export workbooks to HTML files.

Add support for TRIM function. TRIM removes all spaces from text except for single spaces between words.

A list of the supported functions is available at http://docs.telerik.com/devtools/document-processing/libraries/radspreadprocessing/features/formulas/functions

This function can be implemented as a custom function. Check the following resources for more details on how to achieve that:

- http://docs.telerik.com/devtools/document-processing/libraries/radspreadprocessing/features/formulas/custom-functions
- https://github.com/telerik/xaml-sdk/tree/master/Spreadsheet/CustomFunctions

Available in R2 2017 Official Release.

Add support for VALUE function. VALUE converts a text string that represents a number to a number.

A list of the supported functions is available at http://docs.telerik.com/devtools/document-processing/libraries/radspreadprocessing/features/formulas/functions

This function can be implemented as a custom function. Check the following resources for more details on how to achieve that:

- http://docs.telerik.com/devtools/document-processing/libraries/radspreadprocessing/features/formulas/custom-functions
- https://github.com/telerik/xaml-sdk/tree/master/Spreadsheet/WPF/CustomFunctions

This would allow repeating header rows on every printed page. More information related to this functionality may be found on the following link:

https://support.office.com/en-us/article/Print-rows-with-column-headers-on-top-of-every-page-d3550133-f6a1-4c72-ad70-5309a2e8fe8c

If Spreadsheet's history is not enabled, merged cells cannot be unmerged. 

Workaround: Enable the History before calling Unmerge():

workbook.History.IsEnabled = true;
worksheet.Cells[0, 0, 0, 4].Unmerge();
workbook.History.IsEnabled = false;

The COUNT function counts the number of cells which contain numbers.

Description from Microsoft here: https://support.office.com/en-US/article/COUNT-function-A59CD7FC-B623-4D93-87A4-D23BF411294C.

Workaround: Implement such a custom function. See Custom Functions help article here: http://docs.telerik.com/devtools/document-processing/libraries/radspreadprocessing/features/formulas/custom-functions .

The data validation is working. However, the text can't be localized by MS Excel with installed non-English language pack after import/export with SpreadProcessing. The problem is caused by an interpretation of the data validation rule as a text instead of as a formula.

When calling AutoFitWidth on single cell selections there is no issue. However, calling it on a multi-column selection the document is corrupted and repair error message is shown when opening it in Excel.

Workaround: The AutoFitWidth method may be called for each column separately. 

Allow the customers to work with Shape objects.

CellSelection.SetValue method causes memory leak of CellReferenceRangeExpression objects in some cases when cell value is referenced by formulas. The memory leak is small, but the remaining CellReferenceRangeExpression continue to listen to some events, causing performance issues when their number become large - the time to set the value increases with each set.

Xlsx documents with global print area defined cannot be imported. Message box "The name that you entered is not valid." is shown and internally SpreadsheetNameException is thrown. 
By default, print areas are defined in the xlsx files for specific spreadsheet:
<definedName name="_xlnm.Print_Area" localSheetId="0">Sheet1!$A$1</definedName>
but this one is without localSheetId property specified.

MS Excel can import such document and even preserve the area, but do not respect it and doesn't have UI to clear it.

By OOXML specification, this attribute is optional:
<xsd:attribute name="localSheetId" type="xsd:unsignedInt" use="optional"/>

Workaround 1 (includes processing the document with MS Excel):
- Open the document in MS Excel
- Choose Formulas -> Defined names -> Named Manager
- Choose Filter -> Names with errors
- Find all Print_Area defined names and delete them
- Save the document

Workaround 2:
- Delete all print areas with OpenXML SDK


Available in LIB version: 2017.1.213