Which feature within GUI editors allows for setting formatting such as font size, color, and style?

The choice of "Text style options" is the most relevant feature within GUI editors for setting formatting such as font size, color, and style. Text style options provide a direct interface for users to modify the appearance of text elements quickly and intuitively. This includes changing the font family, adjusting the size of the text, selecting colors for foreground and background, and applying styles like bold, italic, or underline.

Text style options are specifically designed for text formatting, making them the preferred choice for those looking to enhance the visual aspects of text within a graphical user interface. This makes accessing and manipulating these attributes convenient for users without requiring direct code manipulation, as it is handled through user-friendly menus or panels.

In contrast, while other features like style sheets or page layout options exist within GUI editors, they serve broader purposes. Style sheets, for example, define the overall appearance of web pages, including typography, but require a different understanding of CSS and are not limited to just individual text formatting. Page layout options relate more to the structure and positioning of elements on the page rather than the specific styling of text itself.