When trying to set the VisibleSize property of RadSpreadsheet on the ActiveSheetChanged event a null exception is thrown in the UpdateSheet method of RadSheetEditorBase. 

Possible workaround is to record the visible size at the SheetChanged event and set it at a later time, e.g. using a timer.

When a row is removed through code and an image is created immediately after that in the same method, the UI does not update. The change is made in the model, but not visualized. If you scroll up and down the change is reflected in the UI.

The SUMIFS function adds all of its arguments that meet multiple criteria.

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

Selecting a column with two or more merged cells, selects not only the selected column but the rest of columns that the merged cells are from. The behavior when working with rows is analogical.

- Async parse of single xml file to speed-up the import
- Allow to import only part of the file
- Respect the widths of the columns and row heights and do not measure them first time in the WorksheetLayout or measure them for the current Viewport only
- Inserting rows/columns also need improvements in terms of performance.

The class would be used for customization of the printing behavior of the control.

Implement automatic completion of cell value based on the values typed above, in the same column.

Setting the visible size property to a small number, like 10,10, will result in missing the last column right border and last row bottom border.

NullReferenceException is thrown when the VisibleSize property of RadSpreadsheet is set more than once on two (or more) adjacent lines. For example:

spreadsheet.VisibleSize = new SizeI(1, 1);
spreadsheet.VisibleSize = new SizeI(5, 5);

To work this around you can increase the time between the settings of the VisibleSize property. For example you can use the ActiveSheetEditorChanged event of RadSpreadsheet and the ActivePresenterChanged event of the ActiveWorksheetEditor, and the UIUpdated event of the ActivePresenter. Each time the VisibleSize is changed, the ActiveWorksheetEditor will be recreated along with its ActivePresenter. You should make sure the second, third, etc. setting of the VisibleSize is executed after the new ActivePresenter is loaded. This can be done in the UIUpdated event.

When the VisibleSize property of the spreadsheet control is set (for example new SizeI(10, 10)) and column is selected via its header (click on it), the IsColumnSelection property of the ActiveWorksheetEditor's Selection returns False. This applies also for the IsRowSelection property.

If you try to filter a column which contains a cell with applied font color and the project is run in debug mode with enabled C# exceptions, it throws ArgumentException at System.Windows.Media.ColorConverter.ConvertFrom(ITypeDescriptorContext td, CultureInfo ci, Object value). The exception is handled and the functionality is working as expected, however this may be annoying during debugging projects containing RadSpreadsheet.

Through the sorting options, the user can set sort orientation (to sort by rows or by columns) and whether the sort should be case sensitive.

If you need to set a custom type number format (using Format cell dialog) and enter some additional text in Type TextBox and press Enter key, the changes are not applied.


Steps to reproduce: 

1. Insert some time in a cell in spreadsheet (22:20)

2. Apply it a custom format that contains AM/PM (e.g. "h:mm AM/PM") and press Enter key

Observed: The AM/PM format is missing

Expected: AM or PM should be shown after the time


Workaround: Press OK button or first click somewhere else in order to change the focus

We should provide an easier API allowing the customers to remove the key bindings or change the commands that they trigger.

Workaround: There is attached a sample showing how all the commands triggered by the key bindings can be disabled.

Images inserted in RadSpreadsheet are resized when the active sheet is changed. The set size is very small, making them almost invisible.

Workaround: Remove the two RadNumericUpDowns in the Picture contextual tab in the ribbon UI. They can be recognized by their bindings, to SetShapeWidth.SelectedValue and SetShapeHeight.SelectedValue respectively.

Steps to reproduce:
- Open RadSpreadsheet with the default Ribbon UI present.
- Insert image using the button in the Ribbon -> Illustrations -> Pictures.
- Add new sheet using the Sheet Selector (+) button, or change the sheet to another sheet
- Return to the initial sheet.

Expected: The image retains its original size.
Actual: The image size is changed to very small one.

Add support for formats which can present numbers with non-arabic numerals, for example:
 
- Bengali - [$-bn-IN,500]0
- Devanagari - [$-hi-IN,400]0
- East Arabic - [$-ar-SA,200]0
- Persian - [$-ar-SA,300]0
- Gujarati - [$-gu-IN,700]0
- Kannada - [$-kn-IN,B00]0
- Khmer - [$-et-EE,1200]0
- Lao - [$-lo-LA,E00]0
- Malayalam - [$-ml-IN,C00]0
- Mongolian - [$-mn-MN,1300]0
- Burmese - [$-my-MM,1000]0
- Oriya - [$-or-IN,800]0
- Tamil - [$-ta-IN,900]0
- Telugu - [$-te-IN,A00]0
- Thai - [$-th-TH,D00]0
- Tibetan - [$-bo-CN,F00]0

Currently, the customers can bind data only to the Workbook property of RadSpreadsheet. Allow them binding cell range to a data source.

COUNTA function is similar to COUNTIF function, but it only counts the non-empty cells. 

Description from Microsoft here: https://support.office.com/en-us/article/COUNTA-function-7dc98875-d5c1-46f1-9a82-53f3219e2509?ui=en-US&rs=en-US&ad=US&fromAR=1 .

Workaround: it should be possible to implement such custom function. See Custom Functions help article here: http://docs.telerik.com/devtools/document-processing/libraries/radspreadprocessing/features/formulas/custom-functions .

If plain text is pasted in a cell, and the text is automatically recognizable as date, number, percentage, formula or other format, the text is always converted to the recognized number format.

Instead, the cell's current number format should affect the convertion in the following way:
- If the current format is General -> parse the value with the automatically recognized format, and set the value with the automatically recognized format
- If the current format is Text -> set the value as text, and preserve the current format (Text)
- If the current format is any other format -> try parse the value with the current format
  - Successful -> set the parsed value with the current format
  - Unsuccessful -> parse the value with the automatically recognized format, and set the parsed value with the current format.

As a result, strings which are recognizable as dates, for example, are pasted as their numeric representation instead of with their Date formatting. Also it's not possible to paste something as plain text. 

Workaround: for always pasting plain text: Create custom Paste button and executes the following code:
this.radSpreadsheet.ActiveWorksheetEditor.Selection.Cells.SetValueAsText(Clipboard.GetText());