When the user clicks in the gray area of the scrollbars, the view could scroll one page at this direction, similar to what MS Excel do. 

This is similar to Visual Studio's IntelliSense, but appears while typing formulas in cells on in the FormulaBar.

https://support.office.com/en-us/article/Use-Formula-AutoComplete-6d13daa5-e003-4431-abab-9edef51fae6b

Allow the customers to work with Shape objects.

#.##0,00;-#.##0,00;;@ does not work in RadSpreadsheet. It should suppress visualizing of ) values.

Workaround: #.##0,00;-#.##0,00; ;@ works fine (there is ' ' [space] set for the zero values).

Add support for creating Tables and applying tables styles (predefined ones or custom).

Implement pop-up providing analysis options and quick access to formatting for the selected range of cells. 

Implement Show Formulas command, which display the formulas in the cells instead of the result value. In MS Excel, this is available in Formulas -> Formula Auditing -> Evaluate Formula.

The keyboard shortcut is "Ctrl + ~".

Implement AutoSum command and functionality. In MS Excel, it is located in Home -> Editing -> AutoSum drop down, and allows fast creation of formula over the selected cell, by choosing a formula: SUM, AVERAGE, COUNT, MAX, MIN, etc. If a range is not selected, the command tries to predict which sells have be included.

At this point, the formatting can be applied only to the whole cell content.