For table widgets, it is possible to assign different styles for different cells. This is possible by selecting one or multiple cells, and select the cell styles in the Style tab.
Currently, the following styles can be assigned:
Background color
Border color, position and size
Font color, size, type and style
Vertical and horizontal alignment
All these cell styles can be switched on and off. If switched off, the style which is defined for the table widget is used as cell style.
To remove all style types of a table widget, select all cells with CTRL+a, and switch the according style off in the Styles tab.