• Create a WYSIWG Editor
• Add a Table with 2 rows and 2 columns
• Select multiple cells by clicking on the first cell and then dragging to the right[Firefox_TableWizard_CellStyling_selection.png]
• Click on the table wizard icon to open the table wizard
• Select the Cell tab
• Change the Background Color to something like red
• Press the Ok Button
• Now the first cell has a red background color and 2 columns are added after the first cell[Firefox_TableWizard_CellStyling_afterCellStyling.png]

Issue is only present in Firefox, Chrome does not allow selecting multiple cells.

The editor used for this was from the Demo Page:

https://demos.telerik.com/kendo-ui/editor/index