When the PrintPreview has to show many UIElements at once, the performance is slow.

This item is moved, because it is related to the RadSpreadsheet's model. You can find the corresponding item here: https://feedback.telerik.com/Project/184/Feedback/Details/255960-spreadprocessing-incompatibility-with-microsoft-excel-of-in-document-hyperlinks

The functionality would allow to zoom the print preview and scroll the resulting viewport.

A partial implementation of the zooming functionality can be found in the attached file to provide a starting point for a custom implementation.

This behavior happens at a specific width of the cell's Column. Using different VerticalAlignment (not Bottom) would workaround this issue.

The PrintPreviewControl refreshes its preview content on change in the SheetPageSetup object. This method would allow on-demand update.

At the moment this can be achieved by changing something in the page setup and restoring it. 

bool printGridlines = this.spreadsheet.Workbook.ActiveWorksheet.WorksheetPageSetup.PrintOptions.PrintGridlines;
this.spreadsheet.Workbook.ActiveWorksheet.WorksheetPageSetup.PrintOptions.PrintGridlines = !printGridlines;
this.spreadsheet.Workbook.ActiveWorksheet.WorksheetPageSetup.PrintOptions.PrintGridlines = printGridlines;

When the formula bar is empty and alt + enter is pressed in order to insert a new line, NullReferenceException is thrown. The exception might be reproduced with text in the formula bar, but the caret has to be placed in the end of a run/end of the text.

Fix available in LIB Version 2018.2.820.

The exception is thrown when the color for the borders has been previously set using the colors from the predefined palette. The next attempt to set a border color using the ShowMoreColorsDialog leads to error. A message appears to the user saying "Specified cast is not valid".

In MS Excel, the users can choose between showing the original size of the page and fit it in the window. Expose a similar option in RadSpreadsheet as well.

The COUNTIF function is already available in RadSpreadsheet.

When the users click on the More Borders option provided in the ribbon UI, the Format Cells dialog opens but the popup of the dropdown is still kept open.

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

Currently, to change the title of the ribbon, the users need to replace RadSpreadsheetRibbon with its XAML code. Expose a property allowing to do this change directly from RadSpreadsheetRibbon.

When the InsertFunctionDialog is opened and the "Go" button is pressed with many words entered in the search terms field, the performance is so slow that the application appears hanged.

Allow loading of dialogs (SpellCheckAllAtOnce and SpellCheckWordByWord) different than the default ones through MEF. 

Use-cases: set different Width and Height, hide buttons (e.g. AddToDictionary), etc. 

- 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.

When the size of the columns is changed using the ColumnSelection.SetWidth(*) method does not update the layout, so subsequent uses of the layout are not calculated correctly. For example BringIntoView method works incorrectly. 

Workaround: call RadSpreadsheet.UpdateLayout() after setting the width.

Cell borders below the cells filled with data are not exported to XLSX.

In MS Excel, the users have the option to specify that the data contains a header row. When this option is enabled, the first row of the column is not included in the sorted range. Implement this option in RadSpreadsheet as well.

When filtering a big range of values, the performance is low. The whole UI is re-created.

Currently, changing the sheets performs heavy calculations on the UI thread. This does not allow to perform any other UI task and the busy indicator cannot be shown before all layers are rendered.