When we want to add a formula in a given cell in the Spreadsheet, we double-click it and enter the "=" in it as an identifier that a formula definition will follow. If we want to include in the formula a cell that is not inside the visible range of the Spreadsheet, we scroll to that cell and select it. In Internet Explorer, if we scroll to a given cell using the arrows of the Spreadsheet's scrollbar the "double-clicked" cell becomes just a selected one and the "=" sign is converted to a string value.
When building a formula in a given cell and trying to navigate to a cell using the scrollbar, this usage stops the formula building and converts the "=" into a string.
When a user creates a formula for a given cell, they should be able to navigate through the Spreadsheet using its scrollbars.