Numbers won't let me change the font style or the color in a cell

After working fairly seamlessly today a Number spreadsheet won't let me change the color or the font style in a cell. I color code cells to show their current state of completion and what I normally do and have done for years is to click on a cell with the current color I want to copy from and then change the cell I want to have the same color from no fill to color or gradient and it has always worked until today. Also I use font styles to reflect intermediate changes and the same thing is happening- it will not let me change the font style within a cell even if I erase and start inputting the text as new- it switches to italic even though italic is not chosen on either styles or under the gear menu. I have multiple restarted and done a Repair Disk under Disk Utilities. Help!