Dialog close button is hidden due to CSS error

When an error occurs, a close dialog button exists, however, it is hidden due to invalid CSS.

The problem code:

background: url("../images/close-sprite.png") no-repeat top 2px


The position parameters here are in the wrong order, causing Firefox to not show the background. The correct code is:

background: url("../images/close-sprite.png") no-repeat 2px top;


This occurs for both the following, and may occur for others too: .ui-dialog .ui-dialog-titlebar .ui-dialog-titlebar-close and .ui-dialog .ui-dialog-titlebar .ui-dialog-titlebar-close:hover