A dialog box may contain unused space along its right side. You can define a text tile and explicitly specify a width greater than the width required by its current value. For example, the following code fragment defines a tile that does not display anything (its value is null) until an application sets its value:
: text {
key = "l_text";
width = 18;
fixed_width = true;
}
The width attribute reserves space for 18 characters in the dialog box. The application can add text with a statement like the following:
(set_tile "l_text" "By layer")
Because "By layer" doesn't need all 18 characters, the dialog box has surplus space along its right side.
A similar situation occurs when you use an errtile to display error messages. (See Dialog Box Exit Buttons and Error Tiles.) Unless an error message is currently shown, it looks as if there is extra space at the bottom of the dialog box. In this case, an extra spacer tile at the top of the dialog box can help balance the vertical layout.